I have a 155G w/ a 35G sump, heavily stocked and I run the ASM G3 with upgraded pump. I swear by this thing.
I'm sure more people will chime in in the morning.
In all honesty, everyone has their favorites, it's personal preference within reason. I ran a Won Brothers for a long time on my 40G and it worked wonderfully as well and even worked on my 155 for two months w/ a medium stock until I got the money up for the ASM. The ASM makes the Won Brothers look like it did nothing.