I have not. But, I have looked into getting one. Here are the reasons I decided not to pursue a track wheelchair.
All the track wheelchairs I considered were too wide. If I remember right, they were all 36" or wider. I could not fit them into my wheelchair van, so would be limited to using them from my house. Those that I have seen with track chairs transport them in the back of a pickup.
They all had very limited range. They take an enormous amount of power and drain batteries rapidly.
The track steer technique used by tracked wheelchairs requires an enormous amount of watts to be delivered to a motor when turning. All the track chairs I looked at had controllers that were too low of power (in both volts and amps). In fact, at least one track chair manufacturer has gone out of business after figuring this out.
Track chairs have a problem going over something like a downed log. If you approach a log or obstruction head on, the front of the track chair lifts, tilting you back. After the center of gravity gets in front of the log, the track chair pitches forward, with you tilting down. I don't think my body could handle that.
Another point to consider is that in the US the federal government has rules about what chairs are allowed on public lands. Those rules require a chair that has 4 wheels and is suitable for use indoors. If the chair meets those requirements, the chair and occupant are considered to be a pedestrian just like any other hiker. A track chair obviously does not meet the criteria and would technically be prohibited from those federal lands.
Instead of a track chair, I got a four wheel drive chair. I love it. It overcomes the limitations of the track chair, except for range. My Magic Mobility X4 (superseded by the X8 in their lineup) has a range of about 4 to 5 miles with MK gel batteries. I am in the process of building a LiFePO4 lithium battery pack for it that should increase the range to 12 or even 15 miles.
Because it has 4 wheels and is suitable for use indoors, I can take that wheelchair on any backcountry trail it can handle in any national park, national forest, wilderness area, etc.
Regardless of which way you go, I highly recommend getting a capable chair for outdoor adventures. Having one has certainly transformed my life!
Steve