Yupp I agree with all of the above
Sounds wierd huh.
Id rate the pumps Ive played with like this.
Sterlings - I still have min nuff said
Phantoms (Well these are good the barrel works out of the box, needs springkit and syphon/anti-syphon though)
Tippman SL-68 (Didn't own it by one of my team mates had one so I've probably played 30-40 hours w that one. New Barrel is a MUST the stock barrel sux. Also this is a rough pump it is VERY durable but tends to be a bit heavy in the pump action.)
Traccer (owned one even played Tourny w. it. Needs a new barrel and a springkit. Also look into a syphon/anti-syphon bottle)
PGP
I have not tried the hammer but according to the ppl using it it is ok.
And now to the part where U'll hear ppl disagree (who mostly didn't try)
For any pump get a syphon CO2 I'd say a 12oz. Why because U can use a lighter spring when drawing liquid and still have the fps. Also if U use a normal CO2 and adjusts your velocity on gas sooner or later U'll use the auto trigger for a while and start drawing liquid and at that moment U'll bounce from 280 fps to 350+ fps NOT FUN!
The alternative is to use a anti-syphon that is the way to go if U allready have one or HPA.