P7s are my favorite series of pistols. I compete with an M13, carry an M8, own an M10 and have owned a PSP.
Some of their best features are accuracy, reliability, speed into action, ultra fast mag changes and safety.
The fixed barrel and crisp single action trigger contribute to its accuracy. Some people complain about the short sight radius hindering real world accuracy, but I have never found it to be a problem.
Have never had a malfunction with a P7 when maintaining it properly and using them correctly. I rarely clean my competition gun and the gas piston will start to bind after about 700 rounds. This has never caused a stoppage during firing, but the slide can be difficult to retract with a very dirty piston. The only failure I have ever had was when using M10 mags in an M13. The mags look similar, but the lips and followers are different. They are fine for range use with 9mm, but I wouldn't use them for carry.
P7s can be put into action very quickly. There are no safeties to disengage or double action transition to overcome. The cocking action becomes very natural.
Mag changes are one of the best features. The M series have an ambidextrous mag release at the rear of the trigger guard and the PSPs have the heel release. I actually use my trigger finger to release mags without shifting grip on the gun. From slide lock simply insert the mag and the cocking lever acts as the slide release. I have found this to be much quicker than retracting the slide or thumbing a conventional slide release. Also the double column frames act as a natural mag well for the M10 and M13 mags' tops which taper to a single stack feed.
I also like the safety features of the P7s. Dropping the gun automatically decocks it by releasing the cocking lever. Also if anyone ever snatched the gun chances are they would not figure out how to use it before you could take action. A US Marshal friend would let other LEOs shoot his and most could not operate it before being told about the cocking lever.
Some complaints about P7s have been price, heat, and loud decocking. Refurb M8s have hit the market and offer excellent value. These can be had for a little over half the retail price of $1,200 for a new M8. The only time heat buildup bothered me was during a class firing several hundred rounds a day. During normal range use or competition they don't get uncomfortably hot. (Maybe I'm immune by now.) The pistol can be decocked silently by pressing in on the exposed area of the frame behind the trigger guard and in front of the cocking lever.
The M8 would probably be your best choice. Prices are reasonable now. Mags are relatively inexpensive. It has a heat shield not found on the PSP and I prefer the non heel mag release.
The M10 and M13 are worth considering. I am rather odd in that the larger frame fits my hands better and I prefer them over the M8. The M10s slide was beefed up to handle the .40 cartridge and it is a bit of a brick. They shoot well and with the right holster can even be carried comfortably. The M13 is my favorite. It fits my hands well, offers the thirteen rounds, and a natural mag funnel. The guns and mags can be pricey now though.
I heartily recommend getting one. Buying used would allow you to get all of your money back out of it if you decide its not to your liking.
Check out www.parkcitiestactical.com for more information. They have a very active P7 board.
Good Luck.