I've got around 3,000 rounds through mine, everything from low-power practice loads with LRN bullets to full-power 9mm NATO surplus. No problems and it still looks brand new.
PWL and Wild Bill's Concealment make leather goods for the P99 series if you need a holster.
CDNN still has a few hi-caps as well, as does KY Imports. Expect about $99 to $125 for 9mm hi-caps. Yes, they are legal - Walther shipped in a boxcar load in late 1994 just before the ban, when the pistol was in final development and a few early examples were in the hands of dealers and military procurement judges.
As others have noted about the trigger, you either hate it or love it. I like it - clean out the firing pin assembly (the instruction book shows you how) and put a dab of good grease on the trigger sear and it sweetens right up.
Ken Strayhorn
Hillsborough NC