Naturally, your best choice depends on the wheeling you will do....as mentioned, in CO you're up against a lot of unforgiving rock and some pretty technical stuff.
I wheeled all over CO with my RK setup for a couple of years and beat on that shit like it owed me money...no problems. Ever. My money is going to them for my '12 build as well.
I'd love to drive a RK-equipped rig. Contrary to my prior builds, my current rig is getting a lot of use as a DD - so, AEV (which seems to be marketed as more of an 'overlander' kit) was my choice. Honestly, the selling point for me was the AEV track day video on Vimeo ... And that my wife would occasionally be driving it with my 4 kids. Marketing koolaid at its best, right?
But, you sacrifice clearance with those front dropped radius arms. I'm 'okay' with that given the 'tamer' trails I typically now run.
IMHO, the RK setup 'seems' to be a better, true dual-use setup where AEV 'seems' to be more of a road setup with respectable, but not the best, off-road performance.
I think RK is right ... They seem to be after two different markets.
Are there really 5100's valved at different rates? How many different rates are there? This has a eyebrow raised.... I'm in the market for new springs as well.
Yes, Bilstein custom valves AEV's 5100s. AFAIK
, the shocks are different on the 2-dr and 4-dr kits (since the spring rates are different on each). I don't know about differences between the different lift kit heights, though.