I gathered you are wanting to purchase a bed larger than a Twin XL. If that's the case, I really can't help you, but would like to give you some information to think about.
First, it is true that Medicaid, Medicare and most private insurances will pay for a bed every 5 years, but that isq after you pay for the 13 month rental (used to be 9 months). After that the bed is yours.
As for features, most brands are comparable. Most beds today are electric and the head and feet can be raised or lowered with an attached remote. The one feature that some beds have (and your caregivers back will thank you for it) is mine also raises and lowers the whole bed. Some electric, some with a crank. My husband is 6'7" and bending over tou change my nappy,wheelchair transfers and bedside potty transfers are much easier. My full time caregiver uses it with the hoyer lift, so she does not have to lift so high.
As for mattresses, so many have been mentioned. But I believe most have chosen the air or at least the gel filled overlay. You also would want a cover that is waterproof (anybody can have an accident). As for me,I'm taking the princess and the pea approach. I'm trying many before I choose.
Also, sheet sets can be purchased at Tar get anytime. Wa l ma rt sells them for back to school specials as college dorm beds are TwinXL.
Good Luck with your purchase,