My '00 ZX3 is going strong, despite some severely neglected maintenance. Never had a problem with it, even though I know a couple are looming if I don't get some work done on it. It's over 160k mi. now.
My '04 SVT grenaded a timing belt pulley, jumped time and bent all 16 valves. At 40k mi, well before the first timing belt interval. Not pleased. From what I gather from the intertubez, this is not unheard of, though far from a common occurrence. I can't afford to throw $2500 at the motor in another 40k mi. when the new pulley breaks, nor am I willing to change the pulleys/belt that often, as I think that's simply unacceptable for a modern car. I'll sell it before it hits 80k, which is a shame, because it's almost everything I want in a car otherwise.
So, mixed experience. I'd say: stay away from the interference motors (only SVT, I believe) and you're in good shape. Anyway, the PZEV 2.3 Duratec motor has a lot more potential than the 2L Zetec in the SVT. The SVT suspension, which I also put on my ZX3, is simply fantastic for a factory design, especially for an econobox.
Despite the expensive trouble with the SVT, I'll probably replace it with a ZX5 with the 2.3 Duratec and a 5 speed, and swap in the SVT suspension. They're good cars for the money.