I feed Wagg Guinea crunch, have done for the last 4 and a half years, using Supreme Gerty Guinea pig before that or pets at home own brand.
much prefer the Wagg over the Supreme as there are less colours added (and the colours in Wagg are natural rather than synthetic) piggies didn't much care for the P@H stuff.
Wagg is also made not too far away from here and i order it from Vet UK, which is based in the same town as Wagg, so it's not being shipped half way across the country to get to me either
i was contemplating that when my herd reduces, i'd switch to a pellet food, but i'm not sure i'll bother as they really enjoy the muesli.
Like others, i don't give them the option of selective feeding. I'm quite a mean mummy - they either eat what is in their bowl or they can go eat hay!
no fresh food until the bowl is empty
i do the same with my rabbits (on wagg bunny brunch) as well