ASM G2 or Coralife 220 Needle Super Skimmer?

[blesum]

120-gallon cool water tank in a classroom. Will be run and maintained by a bunch of 6th-8th graders. There's a "new" G2 for sale in the classifieds here at SWF.com right now for $150. Should I jump on it or just get the Coralife (about $165-170 at a few online retailers)?
I want something cost effective, easy to maintain and doesn't require tuning or adjusting. The seller of the G2 has another thread up from a few months ago complaining that his G2 was blowing micro bubbles all over his tank. ??? He then apparently tried to sell the unit but nobody bit from what I saw. He's selling it again now. G2 for sale thread
I'm not sure I want to run a sump (I understand that the G2 is supposed to be in a sump) and like the idea of having my options open with the Coralife (sump or hang-on externally).
What should I do?
-Blesum

 

[blesum]

*sniffle*
Nobody loves us...
Deal is gone.
Guess I'll stick with a brand new Coralife brought at a vendor instead...
Still might be good to get a response or two on which unit would be best since it seems to be a toss up between these two. That way others can find this thread and have an answer.
-Blesum

 

[jobob]

i was going to get the asm g1 i think, i was at that fish place so i got to open and touch both of them. and it seemed kinda "cheap" so i got the 65gal needle wheel. i got home and hooked it up(easy) and with in 2-3hrs it was pulling crap out. i am really happy with it.