Tuff call,
If you like a full auto kind of game playing upfront suppress and move support gunner. The consistence of the compressed air over Propane/GG is better. Haircut brought up a good point (I'm going to Steal it) once you got the PS engine you can drop it into just about any AK or M4 depending on what engine you go with. You can setup "YOUR" perfect accessories and by the sounds of it you can go from CQB 328fps to DMR 449.8fps in a matter of minutes

. So then give the Polar Star a try.
If you are looking to pick your shots Like Napalm seems to play that type of game and you are looking for a more realistic feel then I would look at the KJW with all the upgrade to get it shooting like a Swiss clock. If you are looking for the best Gas system out there… well from what I have found so for it would be the KWA LM4 PTS/LM4 PTR /LM4C PTR whatever M4 platform or the new release AKG-74M/ AKG-74SU
http://www.kwausa.com/products/professi ... ing/rifles . They are the best stable Gas Gun on the market from what I have found out. Here is a cheezee video from Airsoft GI butit gets to the Meat & Potatoes of its leader in Gas guns.
http://www.youtube.com/watch?v=UvduADSzoEcJust my 2cents.