I went with the IPF SC kit. For the LLT its probablly the most mature in hardware and tuning. It is my almost daily driver so I really couldn't deal with an R&D project. The IPF kit can be installed in a day or two by anyone with a little mechanical knowedge.
I have had the IPF installed for almost 1 year and have had no issues since the install. The extra power is compareable to a V8 and the gas mileage is still great.
When looking remember that the real important part of any FI install is the tune. The LLT ECU is not the friendliest to tune and there are really only a few people that will touch it, IPF just happens to have the tuning capabilty needed to make this kit sing.
http://www.ipf-tuning.com/camaro-supercharger/