Depends on what you want?
Well I tried the Gammo with a view to having it just for plinking, sadly it did'nt come up well even then. If you're after something to do FT with (as your username suggests), then I predict that the gammo will be difficult to produce good results. If your just plinking and it hits what you aim at then a light grease on the seals from time to time and you should be ok.
My best advice would be to research here before you buy anything though, you might find you were about to make an expensive mistake.