I use Lr 4, Cs5, and Elements 10. Personally, I much prefer the pv2012 version of ACR that is available with Cs6, Lr4 and Elements 11.
I shoot RAW 100% but when I started procecssing RAW using Elements, I found the experience very frustrating with the limited controls avaiable with the Elements version of ACR. When I moved to Lr, I found the PP experience much more rewarding working with RAW. And I found that by using Lr, I seldom needed to use Elements/Photoshop Cs.
If you like pv 2012 of ACR better, I would recommend moving up to Lr4 and using ACR 6.7 in pre 11 versions of Elements to move into Elements when you need further PPing.
I agree that if you mostly use ACR, then Lightroom is a better investment. Not only does it have better processing capability, but it has many more tools for you to use.