I can't really tell you what is good or not, but I can tell you my setup.
I have a 29G tank, drilled with a 3/4" hole to my 20G sump. I have a mag 7 return through a SCWD and a mag 5 as a closed loop. I also have ~40 - 50lbs LR and about 2" SB. In my sump I have a CPR bacpak running off a maxijet.
That's my system in a nutshell. So far so good
I like the fluvals. My parents use one in their FW tank. The only problem is they take forever to prime and restart when the power goes out. You might want a little more flow too, but that depends on what you want in the tank.
HTH