Not had experience but heard the Fluvals U1 are meant to be really good, unsure how they do in the tank, you may just have to adapt the flow especially with any baby or small fish about.
I've just bought the fluval U2 for my new 2ft the have a flow adjuter at the top and have a good turnover, quite bulky though, mine will be hidden behind a wall of vallis
Right its sorted, i have a fluval U1 coming next week Urm, seen as i didnt have a filter in with shimmer for the last month i had him can i use a bit of media out of my goldfish filter?