Not much difference
I learned to fly in Piper Cherokees and Warriors (PA-28-140, PA-28-151). I went on to do commercial work in Piper Arrows (the retractable PA-28R) but managed to get some time in C-172s and the US military counterpart, the T-41A. I now own an Arrow so I guess you would call me a "Piper man".
I don't really think it makes much difference. I would consider cost, availability, and (if I planned to buy a plane) what sort of plane I might want to buy. Here in the states, C-172s are much more common and the cost is often a little lower. There are lots of discussions about landing in crosswinds being a little harder in high wing and about ground effect making landing a warrior well a little more difficult but in reality, the differences are not very significant. I do like the visibility when turning that low wings offer but a counter argument can be made about being able to see the ground better in the high wing (good for scenic flights with the family and friends). Some find climbing up on the wing to get in to be an issue while some find needing a ladder (otr having to climb on the strut) to check the fuel in high wings to be more of a problem. For every argument, there seems to be a counter argument.
If your school has several of one model and only one of the other, I'd stay away from the solitary plane. You wouldn't want your education (or worse yet, a checkride) be postponed while the only plane of your model is getting maintenance.
Having said that it doesn't matter very much, I would suggest staying in one model during training. There is plenty to remember as a student without having to adjust to slightly different speeds, power settings, and sight pictures.
So pick one and start to fly. In the end, that's what really matters. Have fun!