1.4's are pretty nippy, have a 90hp engine so
can keep up with a Mk3 Si. But they can't. I do like the silver ones. Having said that they are possibly the most aweful looking car standard. If your gonna get one, make sure you do something with the bonnet or headlights.
Zetec S front and rear bumpers look a treat on them too, and no spraying if you get a silver one as ZS' came in the same silver.
I can say they are a bit rev happy compared to the Mk3.
All in all a good car, will always be in better condition than the Mk3's as the doors are curved rather than flat

engine is less grunt, kinda like a female engine, Mk3 si roars, Mk4 seems to just sound like any other engine.
Performance wise, they are probably easier to mod, intake is actually at the front of the engine rather than the rear so air goes straight in so thats an upside.
Other than that they have gay seats compared to the Mk3 but thats about it and I don't really know that much about them, thats about it.