I wrote this a while ago...I think most of it still applies. Hope it helps.
http://www.airsoftcanada.com/showthread.php?t=88238
I know the "performance" differences between electric/gas guns isn't in there.
Gas Pistol vs. Electric Pistol
- no contest...gas pistols rule
Gas Rifle vs. AEG.....
Gas Rifle
+ more realistic trigger break
+ more realism
+ "action" and "feel" of a shot
+ for most...maintenance, cleaning, operation is simpler/easier to understand
- heavier mags, typically more expensive per mag too
- uses propane/CO2 (so you've got to carry those supplies around as well)
-/+ real capacity mags....realism guys like that, shoot'em up skirmisher guys may think that they're way out ammo'd vs. AEGs
- temperature dependant...CO2 mags alleviate that
AEG
+ more plug+play...add battery, add BBs and off you go
+ when they're reliable...they'll go for years
+ typically more accurate (almost too accurate if you're into realism)
- little/no sound...no action...no weapon manipulation actions
+ no weapon manipulation action = "stupid" simple operation
- you're dealing with A LOT of little bits and pieces when you're maintaining/servicing
- when they break down (and they will)...you're typically looking at bench time
Fun Factor....goes to gas guns (IMO). The noise/action greatly enhances the game play and experience.
My PTW will smoke my GBBR for range and accuracy all day long...but my GBBR is still more fun to shoot and while I'll bring the PTW as a backup/alternative, I rarely use it.