I'd say it's OK but there are better kits out there. I've been running Trail Master leafs since '93 and they have softened up a but but haven't sagged. They ride fairly stiff unless you do stuff like remove the track bars and loosen up the shackles. They actually rode better with the 1.25" shackles I had before. I think it's probably because of the length of the leafs. They're longer then stock and put the shackle kind of far out there, so the ride suffered.
If I was going to go with a lift, today I would spend the bucks for a Rubicon Express Extreme Duty 4.5" lift. It costs more but then you get more too. A lot of stuff that you would probably get anyway. Otherwise, you could piece together your own custom suspension with some nice Alcan Springs leafs. Last time I talked to them, the leafs were $150 each. No other hardware. So you'd need to buy everything separately.
After changing my suspension around and watching my friends do it, I highly suggest you do it right the first time or else it will get expensive. If you've considering 33's you might want to think about going SOA or even SOA/SUA like I'm running. Both of these will require a lot more research and someone who can weld.