I did a search and read alot of posts but couldn't find any kind of concensus. I am looking for one that is very light weight with a good mounting set up, I also don't need it to have any storage. Any reccommendations with these two things in mind would be great.

Dieter CQD, Tango Down or Knights Armament. The Knights or the Tango Down willprobably be the lightest.

Is the KAC plastic or aluminum?  (I'm hoping all plastic myself).

Plastic

I'm very happy with my AAC Verticle Swiss grip.
I like it a little better than the KAC/GG&G. It's slightly longer with more girth.

"...That's what SHE said"

[sex]

I know you're looking for the lightest, but I would really suggest the Dieter.  Once you feel it and compare it to the Knights pattern (which includes GGG's and AAC's offerings) you will notice how much better the Dieter feels.  

I picked one up from Wes at MSTN and chopped it down like the one pictured on his LMT 10" upper.  In one word: AWESOME.  If you email Wes, I'm sure he could give you the individual weights of the Knights and the Dieter (both factory and chopped).

If weight is your criteria, go with the Knights, GGG, or AAC.  If you really want something that feels awesome in your hand, then it's Dieter all the way.

Just my $.02,

Josh

[:D] After rereading my post, I was counting down the seconds for some one to say something.

huhuhuhuuhuhuuh....long.....he said "girth"...huhuhuhu

Just got the Dieter CQD from MSTN and have to say it is very inpressive.  Fits the hand perfectly, solid mount with three points of attachment and has the storage compartment.  It isn't cheap but I still think its well worth  the price.