I'm sure this topic has been beaten to death and I have read some of the threads related to it. I'm going to try three different 2lb lines in the near future.

P Line Xtra Strong Copolymer CXXFG-2 2lb

Maxima Chameleon MOC2 2lb

P Line CXX Xtra Strong CXXC-2 2lb

Found a deal on these lines at fish and save dot com since I was cleaning up on tapered leaders for my fly rods I though I would toss in a few spools of 2lb. Besides it makes pretty good 7x Tippet.
Anyhow I was fishing at my local lake marina (Paradise Point Smithville) and currently have Berkley Sensations 4lb spooled up on my Sahara 750FB mounted to my 6 foot G-Loomis GLII.
There were three of us fishing the same jig and technique over the same brush pile I was catching 3 to 1 fish compared to the other fellows. I was using 4lb they were using 6lb. It was remarkable
on my hook up rate. I'm figuring 2lb would work maybe better. The GLII has a pretty forgiving tip so I don't think 2lb would be too light for the rod. Now lifting the fish up to the dock may be a problem.
I've caught some pretty big trout on 7x tippet with my fly rods so I'll report back in a couple of weeks my results.
I'm thinking of rating these lines on stiffness, durability, memory and knot strength on an unscientific basis just my personal impression.