I use a Prizm on my 77 gal tank and think it works very well. Some are concerned with the noise that the air intake makes but I have tuned it out. Between 3 fish tanks and 3 dogs I can tune anything out
I only have to empty it about once a week and then about once a month I take the whole thing apart and give it a good cleaning. Gets a lot of fish crap out of the water!
It took about 2 weeks of fiddling with the valve and letting it break in before I got the flow/air combo that worked the best. After that, I've hardly had to change, jsut a tweak now and then.
Another bonus I personally like is that it's a fairly slim skimmer and if there isn't a lot of room between a tank and a wall this is great, it sits right against the tank wall and only sticks out about 3" from the back and about 4" from the top