To add to the good advice you already got:
Another important thing to consider is service.
If you are buying one of the major brand ones, you should be able to find someone in your area that services that brand. If you choose an unusual brand for your area, someone would still be able to repair it, but they might not be an 'authorized service provider' and it may take longer to get parts.
You should be able to check on the company website fro authorized dealers in your area.
A last thing to think about is how it is going to be transported. If it's going to be taken apart and put into a trunk, how small/heavy of pieces does it break down into? How easy is it to take apart and put back together?
Not too long ago, someone had posted that her elderly relative went to buy a
scooter and got talked into a power wheelchair instead of a scooter by the salesperson. This should not happen, but it does - power wheelchairs are more expensive and the company gets more of a 'cut'. The salesperson was able to talk her into it partially by promising that her Medicare would pay most of the cost of a power wheelchair. Because of unscupulous practices like this, the rules for Medicare and power wheelchairs were changed in October, making more 'hoops' for people who need them to go thru.
In this case, it got delivered to her house and brought into her living room by the dealer. She was not able to get it out of the house because she had no ramp and it was too heavy to lift. Even if she could have gotten it out, you
do pretty much need a van with a lift or a ramp to transport a power wheelchair. So, instead of allowing her independence, she had an expensive iteme sitting in her living room that she could not use unless she spent more more money for 'accessories'.