I personally like the Fiat, I do like slightly quirky cars and cars that appear to have a personality.
It's not particularly suprising that he car with slighly more BHP and less weight is quicker either. But theres not much in it and it wouldn't really bother me which car won, I would still pick the MINI cos I like them more.
With regards to depreciation MINI is helped considerably by the BMW connection which rightly or wrongly will, for the foreseeable future, keep the residuals higher than the Fiats.
If you want a 500 best buy one now and flog it in the next 6 months while the newness is still there if you don't want to lose too much.