I've never used it; however, you may want to check with local tires shops or your dealer if they will work on your tires later as I've heard some shops in my area won't touch tires if there's slime in them; to much of a mess apparently. I've never seen the inside of a tire / rim after this stuff is put in so not sure how bad it actually gets while changing out tires; makes sense to me though that it would be pretty messy.
Personally I carry a plug kit and compressor with me.
Never used it myself however, everything I've read or heard says that it's a MESS to clean up. I agree with @Kaz, check with your tire shop first. If you do happen to use it, make sure you let the tire shop know it's in the tire before they try to take it off the rim.