It depends greatly on the deity the character worships, but as a general rule I find Evangelist worth it for any d8 or lower class that gets 4 or fewer skill points per level and is 3/4 bab or lower. It's particularly nice for 2 skill point per level classes since Evangelist gets 6 per level. The biggest drawback is that the only strong save is Ref which is arguably the least important, so it is more favorable for classes that already have a strong Fort or Will bonus.
Ironically despite having their own prestige class from the same book, Clerics are actually one of the stronger options for the prestige class with the right deity. An archer cleric of Erastil would work very well in my opinion especially with the Guided Hand feat and the Animal domain.
