If I've got my facts right (maybe wrong so I suggest you do some research), I think the 1.5 engine has a wet belt.
That would put me off, but if it's been looked after, and stays looked after, changed on time etc, it shouldn't be that much if an issue. Very very important to use the right oil and change it on time.
The 1.6 is more thirsty on fuel and older design but more basic, which will mean worse emission quality.