I have some buddies that have the knock-offs. They don't come with templats, so I am told. I am sure it is not the same quality. I guess it boils down to what you can afford and what you want out of the investment.
If I were buying one. I would probably buy a knock-off, just because I need to spend less on car toys and I park my truck in the garage.
I bought knock-off HAM HTs, why not a snorkel?