I've got the 5.5 one. It came w/ a 7W PC and a 16gph HOB filter. I'm currently running it stock except for the light. I have 2X13W PCs over it. I wont lie, they are touchy. I have to monitor mine daily for changes. It might sound foolish but an auto top off wouldn't be a bad idea. I do weekly or bi weekly water changes. I feed 1 drop of concentrated phyto a week.
Mines been running now for about 3 months w/ very good succes so far. Mostly I have zoos, but also a blast, caulastrea and sinularia. I haven't lost anything except for a xenia, but that one got sucked up the intake (not as well attached as I thought) and the propeller destroyed it. I just added some GSP to it aswell.
Get either one, I didn't see the 7" one. Kinda wish i had because of the water volume. I really like it. It's been really fun to work on. W/ maybe one or two exeptions it's as packed as I will let it be. Everything will grow out nicely and if shouldbe fantastic. Give it a shot!