Right, serious cap on as I test drove one, researched into it when looking at cars and drive a (non-vRS) Fabia from time to time.
Engine wise, it pulls well. Bear in mind that it's never going to set any speed records though, and going around corners you have a heavy lump right over the front wheels. It's also very dagdagy sounding, but this won't bother some people.
If the mileage is around 60K or higher check for a cambelt change, or factor it into the price. Also bear in mind that higher mileage ones will have the usual potential injector bills, but on the whole the engine is quite sound.
Er, interior is a sea of nasty plastic but just like the sound, that won't bother some (personally I found it well put together so i'm not fussed) and you get a choice between some black/white cloth seats that seem to be a **** to clean or leather ones.
Try not to get ripped off as it's easy to be with these cars, and you should be fine.
[Edit] Cambelt is 4Y or 60K, so anything you look at should have had at least one change, and potentially getting close to a second.