A couple of weeks ago I took the plunge and decided to be one of the early adopter 'beta' testers of the 3M Paint Defender product.
I chose to only spray on my bumper and forego the hood or mirrors. I was afraid I might not like the look on the hood so I figured I'd try the bumper. I bought 1 can and the prep kit, total was $36. I was apprehensive about the prep kit being overpriced, but it turned out the plastic film and tape was worth the convenience. I chose not to buy the spray nozzle and had no trouble with the can.
Long story short, it took about 2.5 hours to prep, and 10 minutes to spray. I read a lot of stories about it not being installed thick enough and people ending up with an orange look. So naturally I sprayed it too thick in a few places, with the worst part shown in the pic below. The directions say you can't reapply after 10 minutes (basically once it's started drying). It started running about 20 minutes after application unfortunately so I tried to stop the running with a hair dryer. I was very mad at the time and assumed I'd be peeling the stuff off as soon as it dried. I slept on it and decided to leave it on. 3M says it will last a year so I figured I'd put up with the imperfection and see if it prevents some chips.
One thing I failed to realize was that it can't get wet while it's curing (2-4 days), even though it dries in 4-8 hours. Rode my bike to work in the rain and had fun explaining that to everyone, lol.
Overall I'm happy with the look- can't notice it whatsoever (besides the run) and it feels thick and like it will protect from the smaller rocks. I waxed it yesterday and now the feel is almost identical to the non-sprayed parts of the car.