did I say that I used one NO!!!!!!!
No, however you HAVE been known to make comments that would indicate that you have used both markers in a game situation and are familar enough with their functionality to make a reasonable comparison between them, had the comment come from a more reliable source.
From what I personally know from in game experience is that out of the open-bolt blow-back sidearms out there the Zeus is the best. I have at one point or another used the entire PT line except the professional (if you want to make a comment about a pistol that is a replica of the Enforcer, choose that one.) I know that the PT extreme performs very well, but has a finite life span of perhaps a thousand shots before its valving degrades enough that it no longer is able to get a paintball to reasonable velocity (Unless the 120 is reasonable to you). I know the entire PT line has this problem. I also know that the entire PT line uses mamoth bore sizes (over .7 inches) for no apparent reason, which lends itself to accracy problems and contributes to it's low velocity. I also know that the PT manuals aren't anything to brag about. The diagrams are only slightly more useful, but they make up for it with a bad translation (alien renches for example).
Now as far as the other types of sidearms go, here is what I also know. The Sydarm (dbaily got this one right) is a modified automag made by AGD. It is almost an exact replica except for it's more compact size and the fact that it has been modified to accept 12 grams as a power source, and has a 10 shot spring assted clip at the top. It is open-bolt blow-foreward, and will experience the same chopping problems of the regular automag without the LVX bolt kit. The PGP is a stock gun meaning that it uses a 12 gram for a power source and recocked by means of a pump mechanism. It also has a 10 shot clip on the top of the gun that comes standard with no assisted feed (Which aren't allowed on a stock class gun) The phantom is very similar, but it has a smoother pump action, greater air effeciency, and a significantly reduced weight.
Now, if you want a pistol and price isn't an option, I'd say you have to go for a Squall made by palmer (palmer-pursuit.com) Essentially it is a heavily modified PGP that is semi-automatic. It is also the only pistol you can find off the shelf that is both closed-bolt and semi-automatic.