Ariakon Overlord : too breakable, too heavy and lacks the PG's accuracy as far as I'm concerned.
Zeus G2: Only used as a loaner when aforementioned Overlord died, but more favorable.
Delta 68: Don't bother.
SL-68 Pump: Rugged and reliable like the PGP, but not as accurate, and the ancient 40 round hopper is a pain in the butt to reload.
Tippman Pro Carbine with an 18 inch barrel and an expansion chamber. Ariakon Overlord in a custom cross draw holster.
None, unless you would like a lanyard ring for the back of the feeder tube.
Accuracy, Reliability, Manueverability, Draw Speed, Balance, C02 efficiency, I could go on...
The highwaymen that run the Crossman repair shop.
The PGP2 was my first stock/pistol marker, and I bought mine for 100 bucks from the now closed Splatz paintball in Bangor Maine. I snagged myself a 20 dollar tac holster to wear it in, and a box of CO2 cartridges and headed for a pickup game the day after I bought it. The game was 3 on 4, in a semi flooded gravel pit, with spruce forest and muddy moose wallows. I had been practicing and chornographed my PGP on cans and my .22 pistol target the day before, and was hoping for the extreme accuracy it showed during practice. The PGP payed off with taking out an electric auto wielding player with the first ball out of it, and I fell in love with this awesome little pistol.
Over the next few years of paintball and woods capture the flag tournaments, the PGP became more and more my primary gun. It really was the ticket in games with small numbers of people, especially when stealth and woodscraft was a part of the game. I became so comfortable with this gun that I found myself tossing my always chopping Diablo Mongoose and charging into situations with the PGP in hand.
The major strength of this little marker, is that it just shoots straight. The ball flies out of the barrel in a straight line ,especially if you use larger bore paint. This lends the gun to many long distance shots, as with a little experience you can quickly elevate you're aim and become a terror from quite a distance. A memorable moment was knocking out a player harassing our group with a flatline A-5 with one ball from the PGP.
Unfortunately, all good things must come to an end. This was sadly true with my little PGP. After four years of playing hard, in all sorts of weather, arena's and games, somEthing I can't figure out just quit inside the little gun. I attempted to revive it by sending it to the Crossman repair shop, but that was the biggest mistake I made. These guys are a bunch of pirates, my gun was gone for four months, I was out 80 bucks, not counting shipping and handling, and the marker I got returned to me just was still not operable. My problem had been a broken CO2 piercing knob, but what they had done was somehow hammer in a cartridge till it took, and then they wrapped up and shipped back my PGP, (gassed up and loaded mind you) through the mail. When I recieved it, I went out to test fire it, only to discover the gun was already gassed up. It took 2 shots, before the CO2 inside expired, and I could not get another one to take for the life of me. So now my PGP is relegated to it's box in the top of my closet. But I do plan on getting another soon!
If you play woods, scenario or pickup ball, this pistol can be your most trusted marker, primary or otherwise. I will step up on a soapbox and say that it is the best production paintball pistol made. Compared to this relic from the time when paintball was PAINTBALL, most modern pistol designs are poorly balanced, gaudy, accessories.