I have a rear entry, manual ramp (2014 Toyota Sienna). On the plus side, I don't have to park in a van space, though backing down into a busy street or parking lot can get hairy. I face forward and can converse with occupants in the middle seat, though I often can't hear the driver and the driver can't hear me. I get a lot of road noise in the back. Also, the incline on the manual ramp seems significant. A power lift would surely be better.
I just purchased a used Toyota Sienna with a side entry ramp - the angle of incline is very small, So it's very easy to get in and out. I think the advantage of a side entry is that you can park your wheelchair in the middle row, right behind the driver and front passenger, or the front passenger seat can be removed and you can pull your wheelchair right into that spot.
As @nona mentioned, though, if another car is parked next to you in a parking lot, you don't have room to deploy the ramp. But, the car can always be backed out of the spot a bit, then deploy the ramp. Also, if you park on the street, there might be obstacles - such as a curb, parking meter, trees - that would make deploying a side entry ramp difficult.
Since I don't have kids or other family members, it will normally be just me and a caregiver/Friend as the driver. So, I would prefer to be up in front so I can converse easily with the driver.
Currently, I can still walk pretty well and I can transfer out of the wheelchair into the front seat by myself. So, right now, side or rear entry ramp really doesn't matter. However, later, when I'm not able to transfer out of the wheelchair, the side entry will be better for me.
My husband and I recently purchased our 2016 Honda Odysey van equipped by Braunability with a side entry automated lift. As mentioned prior, parking is an issue to think about, but, as Nona mentioned, I believe the placement of your wheelchair is most important to consider. I can sit up front in the passanger area with the very easy removal of the front seat which rests on wheels. This is my preference when traveling anywhere. Or if traveling with another couple, the front seat can remain in and I am anchored into the middle open section with other guests seated behind me. The van is equipped with hydrailics to lower on the ramp side to a level making the ramp less steep. A mobility dealer will show you the options and help with your decision. I hope this helps. Ask if you have further questions. Others here I'm certain will also offer their experience.
We bought a used Toyota Sienna in January with side entry. I thought we would be able to do more outings with it and then the coronavirus hit. I'm really glad we have it, though, as it has allowed me to take my PALS out of the house to the park or the beach; I try to plan a fun outing for him at least once a week. I also have needed to take him to urgent care, the hospital for the feeding tube surgery, and the bank. We've taken out the front passenger seat so my PALS can sit up front and critique my driving...
I think the big considerations when it comes to configuration are side entry vs rear entry, ramp vs lift, and manual vs power.
If you live where most parking is parallel (think big cities and parking on the streets), then a rear entry van will not work very well. You will always need a space behind you so that you can unload and that will be had to find.
If van-accessible handicap spots are in short supply and you will be parking in a typical parking lot, then a rear-entry van makes a lot of sense.
With side entry, you need a space beside you. That can be the striped area adjacent to a van-accessible wheelchair space or it can be the sidewalk when parallel parking.
One of the rear entry vehicles we looked at required the doors to be opened and the lift operated from the outside (I don't know of any power operated rear doors). That meant I could never use it by myself. That would be unacceptable to me.
Before deciding what to get, we did a tour of our local area, checking out the availability and arrangement of handicap parking spaces. There is almost no parallel parking where I live. Deciding on a side entry van was an easy decision.
The most mechanically reliable solution is a manual ramp. You simply open a door and fold out the lift. But, it requires an able-bodied person to deploy and stow the lift, which will limit the ability of the PALs to take trips independently.
Ramps are typically only available on minivans. Minivan conversions typically have a fairly low carrying capacity (in terms of weight). By the time you load a wheelchair and occupant along with one or two passengers, you will often be near the vehicle's Gross Vehicle Weight Restriction (GVWR). That means loading a van with everything needed for a trip could be problematic. While space will be an issue, the weight restriction of the van will often be the limiting factor.
A power ramp is more complex than a manual ramp and has more ways to fail. However, most have a manual override so an able-bodied person can still deploy the ramp if there is a failure.
If you want more carrying capacity and more space, you will need to consider a full size van (Chevy Express/GMC Savana, Mercedes Sprinter, Ford Transit, or Ram Promaster). I have never seen one of these with a ramp. They typically use a power lift, which is mechanically much more complex than a power ramp. Ours has failed countless times. While there is a manual override (requiring a special tool and lots of effort), it is not practical to use it on a regular basis. After enough failures, I was about to figure out the root problem and repair it. Our lift has been 100% reliable for over a year now.
Also consider that all minivans and some full-size vans have a dropped floor (with a lift kit in the suspension). This is a major modification to the vehicle. I have read many reports that these conversions are very prone to rust (much more so that a normal car). I am not a fan of such an extensive modification to a vehicle. Vehicles are very complex and very carefully designed. I believe the fewer modification, the better.
We have a full-size Chevy Express with a raised roof, but without a dropped floor. We bought it used with about 80,000 miles on it had have put about 120,000 miles on it since. It has exceeded my expectations.
There are also some more esoteric conversions such as pickup truck (All Terrain Conversions) and SUVs to consider. I think most folks here will gravitate toward a van, but I personally lust after a pickup truck! They are insanely expensive.
Here are my essentials when looking for a van. Yours may differ:
1. My wheelchair must fit. In fact, we often travel with 2 wheelchairs, so two wheelchairs must fit. It is amazing how many vans cannot accommodate a tall rider in the kind of wheelchairs I use.
2. I must be able to enter and exit the vehicle without assistance. That means I must have a way I can open the doors, deploy the lift, stow the lift, and close the doors. It can be awkward and inconvenient for me, but I must be able to do it. Essentially, this means I would like power doors. My current van does not have power doors and I wish it did.
3. I would like to be able to enter the vehicle without reclining the wheelchair. On my current van, the entry is low enough that I must tilt/recline to enter.
4. I would like remote start. Operating my lift without the car running puts a big strain on the battery. We typically go through an oversized-battery every year.
5. I want to have enough ground clearance to easily go over the most aggressive speed bump. That has been an issue with the minivan conversions we have rented.
6. A 1/2 ton full size van just does not have enough carrying capacity (weight) for my wife, me, 2 wheelchairs, medical equipment, and luggage for a trip, We have extra springs in the rear, which help a lot. We are generally driving around near the GVWR (as measured by a truck scale). I would really like to have a 3/4 ton or 1 ton van.
7. We want to be able to access the middle-row seat from doors on both side of the vehicle. It is hard to find a full size van that has driver side doors for the middle row.
8. I would really like to have 4 wheel driver or all wheel driver (we live where it snows a lot).
9. It must be side entry
I would also like the van to be reliable, require low maintenance, be cost effective, and be comfortable.
If I could find something that met all the above criteria, I would buy it tomorrow. Such a van does not exist. The closest matches I know of currently are a Mercedes Sprinter and a Ford Transit, each of which have their own drawbacks.
Now, with all that said, most people wind up with a minivan conversion. Of those, I think a Toyota Sienna would be a good choice, if your wheelchair fits.