I agree you can get a basic Fabtech for as much as a Rancho or a Pro Comp for even less, but sometimes you may not want that extra 2" and that's a tough decision to make. I use my bed often and every time I load something big I find myself saying I'm so glad I didn't get a 6" kit! I didn't even consider Rancho until I was parked at a light in DE and saw a truck with it across from me. It was the look I wanted. I picked up my Rancho for $1,800 on sale, shipped, with shocks. I thought that was a pretty good deal. Plus most of the other kits state the stock wheels won't work, but I was able to use the stock 20's, which I like very much, so that was a big savings there also.
I had a 2.5" leveling kit on before and I think there is quite a difference, but I was also running my stock tires with that leveling kit. I remember the first time I got in my truck after the lift, you know how you get that muscle memory of how high you have to lift your leg to get in the truck.... well, I came up a little short and was moving too fast up into the truck.. didn't quite make it in! Also, I tore a CV boot with my 2.5" leveling kit and I've heard a few others do the same. I don't even take my truck offroad. I felt much better getting a suspension kit that kept my angles the same.
I installed the kit in my garage with some friends. It was the second lift I'd put on a truck, plus I've done a lot of suspension work on other cars, so it did seem pretty easy to install. It could possibly be a little overwhelming if you don't wrench much and you're installing it in the driveway on jackstands. Here is a link to some pics of the install: Rancho Install