Well I'm running a 2nd-hand Daystar lift that I got off signcutter21. I've put about 15,000 on it with no real issues. He did replace the front shocks with Ranchos (not sure if they are the 17505s or something else) and I replaced my rears with Rancho 17004s for the extra travel. One minor criticism I have is that the front end seems to have limited compression with stock springs; it seems like the springs reach maximum compression before the suspension reaches the limits of its travel. Other than that I have been pretty happy with the lift. I may see about replacing the springs at some point but thats down the road a ways. And here's a picture of the lift in action a couple of weeks ago:
To answer some of your questions, you'll need all the standard tools (spring compressors and such) if you plan on installing the kit yourself. As for longevity, as I said I am the 2nd owner of this lift with no issues. I know some others on here have had theirs on for a few years and I haven't seen any complaints (that I can remember). And yes your mileage will suffer some with the lift and larger tires, how much depends but it will go down. If you can find some extra rims to keep some road tires on that is one way of lessening the impact on mileage, but then you have the fun of swapping tires whenever you want to go play.
Hope this helps.
