Remember that it's not just about the lift. The reason for lifting any vehicle is to put bigger tyres on it, as you're only ever as high as your diffs.
That said, the Cherokee is particularly prone to spending half it's life on it's transfer case crossmember. I run a Rusty's 4½" lift (with adjustable lower control arms) and 31" tyres. At that height, it also needs a 1" T/C drop kit to re-align driveline angles. Be warned though that if you're gonna go that high and are less than 6' tall it might be a struggle to actually get in - I cover my trousers in mud from the sills every time (and I'm 6').
Having said all that, she flexes like crazy and hasn't bellied out once since fitting the kit. About £750 delivered from the states.
You need to ask yourself how much you want to spend, and how big you want the tyres. You can get some pucks to put on the springs for a bit of lift for cheap, but although it will give you a bit more clearance on the body, your diffs will still be low. From what I've seen of that kind of lift, I'd avoid it - you're still on stock springs, only it won't flex as well.
Tyre's upto 31 inches you can use a lift of 3" (min). If you want bigger tyres, then you'll need more lift, but also cut-out fender flares, a slip-yoke eliminator, an axle strengthening kit and different gears in your diffs. That's gonna cost you big bucks (Probably above £3000 plus tyres and wheels).
My advice would be to do the job right first time, getting as big as lift as you can reasonably afford, but without breaking the bank. That means a 3-4½" lift on 31" tyres.
Have a look on 4wd.com and quadratec.com - the exchange rate is crazy at the mo, you'd be flushing your money down the bog buying in the UK.
