I had the opposite experience with this. I completely agree that the price makes it appealing, and the overspray seems to disappear easily, but I found it barely lasted a week. It was even worse than the autoglym spray on stuff I was using before it.
I bought it based on the strength of reviews and wondered if I got a bad can, but mine certainly didn't live up to my expectations.
Did you make sure the tyre was completely clean first? A good covering with APC, scrubbed in with a coarse brush and left to dwell for five mins, before rinsing then washing the rest of the car (and doing the tyres again then) helps. Always separate utensils for wheels and tyres of course.
I spray on Tyre Slik and then rub off the excess with a mf. Longevity is really quite good even compared with Megs IME.