You've just unknowingly opened a nasty can of worms. You're going to hear from everyone that "xxxxxx" is great and "yyyyy" is garbage.
It's your car and money. Take the time to figure out what YOU want by looking at everything from each point of view, what your ultimate goal is, what you want to do with the power, what your state will allow due to "smog constraints" etc. Nothing is worse than making a purchase for several thousand $$$'s only to find out that your not happy.
That being said, I have had both a Vortec SC and a STS Twin Turbo kit. I liked things about each, but I was happier with the STS kit. If I remember correctly, I got more torque from the Vortec with lower boost (6-7 lbs), but had better control of the STS kit. After a while I added more boost and saw larger gains because of the extra boost (up to 12 lbs). I didn't need nor did I want more than that. I couldn't keep the tires planted.
I liked the STS kit because it didn't fill my engine bay with turbos, heat, tubing, etc. I like having the extra room when needed to work on that part that WILL fail. As far as turbo's go, you can get all you need boost wise with the kit. Some people swear that there is significantly more "lag" with the STS kit, but you can adjust for that now and STS will help you find the right setup if you're concerned about it. (if that were to be what you wanted)
There are other turbo companies out there, turbonetics, HKS, AVO, etc. All of them will have turbo kits for the Camaro in due time. That is what they do. Who's the best? That is an even larger debate.
I liked the SC, but it took more time to get everything right on my setup. I had belt issues, pulley issues, and stupidity issues. (I listened to the wrong guy and added a 50 hp shot of nitrus to cool the air temp going into the SC and blew my big $$ manifold apart when it wasn't tuned properly) :mad0260:
When the SC was dialed in, it was on. :thumbup: After a while I wanted to try something new and went to TT. Then I had a hole new set of issues. :mad0259:
Here is a good read to help you out:
http://auto.howstuffworks.com/question122.htm
Hope this helps, and good luck with your search.