Muck off for me too but don't put it on until after you have wet the bike first as I have found that it can be a little strong strait from the bottle.
I first saw it at a kit car show, the seller was banging on about how good it was when I noticed that the wheels on his van looked like they had done 100,000 miles without a wash. I asked if I could try it on one of his wheels to which he answered "You can clean them all if you want". Cheeky! Anyway, he splashed a little water on a wheel, sprayed it, gave it a quick brush then washed it off. Magic, it was gleaming.
I bought a 5l bottle and have been using it ever since, it's not expensive and it's quick leaving you plenty of time to take your bike out and get it dirty again safe in the knowledge that it will not take long to clean it again when you get back.