I have driven both but only the current MINI and the last of the Golf.
What I can advise, is drive both and more importantly drive it around to your mom's and see which is easiest for her to get in and out of.
I once had a Beetle Conv't and drive it to Greece from Germany to visit family. Having the quick folding top was a plus for an uncle who struggled to get in and out of most cars as I was able to drop the top and he stepped up and into the car. Oddly enough, he found it easier to do this going into the back seat vs. the front!
