well the 05-07 are newer and you should have a better chance of finding one in better shape.
The only real issue I've had in the past 5 years with my '07 was the alternator going (same for my sister who also has an 07) Other than that, just normal maintenance related to wear/miles. The motor has been strong and issue free for me.
If he can find a 03-04 zx3 with a 2.3 duratec, 05-07 st, or a good condition svt; I'd go for one of those. I'd take a lower mile 1.5gen vs the same mile 1st gen. The zetec's from the 1 gens are still good motors but stay away from the spi's.