It's not hard...like earlier poster said, the first cut is a doozy but after that point of no return, it aint so bad. There is nothing technical about it...line the new flare up, trace the opening, cut metal, and bolt it up. If you make a crappy cut, the flare should hide it...unless you cut way too much. Not much room for error on top...there is moreso on the sides.
Considering lifts are the other methods for getting more clearance, I'd say it's definitely worth it. Lifts have side effects like reducing gas mileage, affecting handling, etc. Flares don't have any of those negative aspects and it's a cheap mod. But in the end...I say lift your Jeep and put it on at least some 32's!!!