they are both really good, and very durable! The star tends to be less stable than Champ in a particular mold. But sometimes thats a good thing! I use my star destroyer for drives with no or little wind, but will switch to the cfr destroyer in champ plastic for more windy situations.
I'll second this post.
I carry 7 molds, and for a few of them I carry DX, Pro, Star or CH because of the flight differences.
1 CH Gator, 5 Rocs (1 CH, 3 Pro, 1 DX), 2 Teebirds (CE TL, CH T), 3 Orcs (2 Pro, 1 Star, and I need to get another CH Orc), 1 Star Wraith, 1 Star Destroyer, 2-3 Aviars (Pro, Star).
The CH and CE discs I carry because I want that disc to be overstable longer, and like someone said, when they do get broken in, they stay that way for a long time, like the 1st run CE TL ... it's the freakin bomb, and it's the oldest disc in my bag ... yet in the best shape!
I like the feel of the Star plastic and it's grip, but I can't really tell a whole lot of difference between the two unless it's wet. Star is very grippy even when wet, but DX is even better, CH can be kind of slick. I can't play with a lot of DX though because the CO terrain will eat them up! I have to add that Pro, or KC Pro plastic is awesome and some of my favorite discs are KC Pro/Pro plastic.
My one and only gripe with Star is that it occasionally "cuts" easier than CH. Hitting a sharp basalt/volcanic rock with a Star discs can really suck. I've had to replace a couple of really nice discs because of this.