Here's why I like mine, a P7M13...
It has a full-length barrel, but the gun really just isn't that big.
Because of the type of action (gas retarded blowback) the bore axis is very close to the top of the hand. This makes for more natural pointing ability, less felt/apparent recoil, and faster follow-up shots.
EXTREMELY accurate. Off of a bench at 15 yards I have little trouble cutting 2" groups.
Excellent trigger.
Extremely safe. If the squeeze cocker isn't held back, it's not going to fire. More than one police officer (New Jersey State Police and US Park Police) have had their guns taken from them and the bad guy couldn't figure out how to operate it.
Excellent combat-style sights.
Drawbacks?
The manual of arms takes some getting used to.
I find the grip on my P7M13 to be a lot blockier than the grips on other high-capacity semi-autos.
The firing pin retaining collar is a known weakness. If you get one, inspect this part regularly for cracks.
Magazines are very tough to come by for the M13, and are very expensive. I had a guy try to sell me one for nearly $200 at a show. On the plus side, though, the mags are built like TANKS.
Leather can be kind of tough to come by, and there aren't a lot of styles that can be had at your local gun shop. You normally have to order.
Finally. The BIG drawback?
HYPER expensive. I'm glad my P7M13 was a gift.