They do come up quite often but that one does look particualrly tidy.
They can fit 4 adults, but it can be tight. I have carried 4 adults, including myself from London to Bristol in my Fiat 500, which is even smaller than the 126, but very similar.
They handle beautifully, can cope on dual carriageways, but do struggle if you try to push it over 70mph.
If they are well maintained, they can be very reliable, but they do require a degree of TLC. If something does go wrong, they are pretty simple to fix/source parts for and you will get mountains of advice from the good people on this forum.