I was a "brony". I was totally into G4 and loved it. I helped with the starting of Bronycon, one of the first MLP conventions. Was in the thick of it all and it was a wild, fun ride.
I gave G5 a chance. I really did. I just couldn't get into it. It's hard to describe, but G4 felt like it had genuine passion and love in its production, and it really showed. G5 lacks this; it feels kind of cold and sterile, like the heart has been taken away. The first movie was probably the best of the G5 content and then it sorta want downhill from there.
I still love MLP but will always consider myself a G4 fan. The existence of G5 doesn't affect G4. I think the right people just came together for the production of G4 (especially Lauren Faust) and it was a masterpiece, and this didn't happen with G5. Hasbro should have continued and evolved G4 rather than wipe the slate clean.