Pistols are a niche marker, but they definitely have their place in outdoor fields. A close-mid ranged shot where you want to expose as little of a target as possible? A pistol will give you that option as it doesn't have a hopper. I've also used it to suppress a second target while advancing on a first.
Finally, they're a good bunkering tool as you can reach around and get that shot off without fumbling with the weight and bulk of a normal marker.
I have a Zeus G1+, which has served me extremely well. After tuning the springs I get about 18-20 shots from a 12g at ~270 fps which isn't bad for a blowback. I've heard great things about the Tiberius 8 as well, but I'm turned off at the concept of the clips -- too much money for what really boils down to a novelty loading system. I prefer feeding mine with 10-round tubes, so with a mere inexpensive wrist harness I have the option of having up to 50 pistol shots if I need them in a big game.
...keep in mind I run a pump as my main marker, though. The firepower a compact one-handed semi offers is a lot more valuable to me.
