It's definitely worth it if that's the look your going for and it allows for 35" tire clearance at stock height in the JK's. Their obviously not as strong after the cut (you can stand on them or anything) but there not as flimsy as your think. The hard plastic under the visible flair is cut with it and it has the plastic Christmas tree headed bolts to secure it down so it's not like they're flapping in the find or anything.
There are quiet a few write up's on here about how to do it, all in all it takes maybe 2-4 hours from start to finish (and that's being very careful to cut in very clean lines). A little advice after doing mine... don't be overly critical of how clean the cut is, a little sand paper will smooth it out and the edges get covered by weather stripping after. Plan your cuts ahead of time and mirror them, I used cardboard to measure and mirror cut the fenders and in the planning process I cut close to the remaining supporting structure attachments so it's still strong for what's left over.
Here's a few pictures of mine.