The P7M8 and P7M13 are called "squeeze cockers" because the front grip strap is the cocking and safety mechanism (if the front strap is not pulled / squeezed to the rear, the striker is locked in the "hammer down" position).
The other feature I like is the mag release: It's not a button that pushes into the frame, it's an ambi lever (like a slide release) that can be hit with the thunb (works OK) or the index finger (works great / very fast).
Both are 9mm. Both have polygonal barrels (as do most / all HKs). The M8 is 8 shot +1 the M13 is 13 shot +1.
IIRC, I paid ~$600.00 for the M8 about ten years ago, I got the M13 (plus cash) in a swap for writing a database application for the gunstore the year after that. The last time I looked, the M13 was ~US$1300-1500.00 and is not generally available (except used or "new old stock" because of the "assult weapon" rules of a ten shot magazine restriction.
I also have a Sig 226 (K-Kote, tritium sights), IMI Jerrico 941 (now called a "Baby Eagle" the kit has setups to make it a 9mm or .41 AE), and some others (had Glock / don't like Glock / sold Glock). If I could only keep one, it's be one of the P7s.
I don't shoot as much as I used to. I've looked at the USPs and other HKs. They're still a big favorite.
My other favorite pistol is a Colt Delta Elite (stainless, first edition) 10mm (Bren 10, not the wussy .40 cal stuff they're selling today - scaled down from a REAL round so the sissy FBI accounting-degree-weenies can shoot it without messing up their calculator-button fingers

(( Just Kidding FIBBIES!))).
The pistol most associated with James Bond is the Walther PPK, which replaced a Beretta .22 .... I think in "From Russia, With Love" or "Dr. No"
FWIW
Scott