Welcome to AO.
Couple of pointers;
1) Check oil levels to determine if previous owners looked after it. Twinsparks can drink a liter per 1000 miles!
2) Cambelt (as advised by Mike). Current wisdom is to check/change at 36K not
72K. If the service history doesn't show this as having been changed already then get them to do this as part of the sale (I did
). You will only need to do this yourself anyway.
5) Did I mention the Cambelt?
There are buyers guides for the 147. Do a serach using the function at the top of the page and you should find some other threads on the subject and some links to some external websites (AROC for example) who have guides with good advice.
As for the reputation, don't be put off by the bad press. A lot of that comes down to the widely held perception that the dealer network is rubbish. However, there are plenty of good, well recommended Independant specialists who will save you money as well as giving a high level of service. Also, the more recent models (147 amongst these) don't have the reliability issues of older versions.
Don't expect 100% trouble free motoring, there is just too much Italian character in the car for that to be the case but IMO the driving/owning experience is more than enough of a reward to offsite a few technical glitches!
Ultimately, if the car doesn't feel right, don't be afraid to walk away and look for another.
Good luck and happy motoring.