i think if you have a bun thats prone to a mucky bottom, SS is the way to go. If your bunny doesnt have that problem, excel is fine.
None of my bunnies have had mucky bums ever in their lives, they just dont :lol: so they had excel. But cotton (foster) im giving him SS as he is switching over food and want himt o have a high fibre food as hes so little.
but Excel is fine, especially if you have no tummy problems.
I had a boarder once whos bunny had a mucky bum 24/7 despite loads of hay and no veg, and i tried SS with her and now shes always fine and can have veggies again