That's interesting @ChezaH, as I'm also on Genox. It's just what my chemist stocks, so I never tried the brand name one.
I wouldn't have thought brands could make a big difference. My husband always gets dismissed by the chemist but insists that ventolin works better than the generic. And I was just chatting to the person injecting me with radioactive tracer and he said the brand of what they inject you with during a CT can effect how much you feel like you've peed yourself (as I'd just had my CT and it wasn't anywhere near as bad as the one I had 20 years ago!!).
Either way, I'll stick with the Genox for now since my side effects seem pretty good compared to many.