As a person that has been involved with NAVHDA for the last couple years and founded a chapter, I'll give my two cents. I own a small munsterlander, researched the breed and breeders and settled on a pairing that had lots of great testing/drive in the lineage and my pup is everything she should be, her only weaknesses are because I'm still a novice trainer. That said, they are hit and miss as a breed, do your homework.
Consistently, the best dogs I've watched work through several training days and tests have been Drahts, and GSP's, but coincidentally, those have also been the dogs with the best trainers I know. Vizlas are known for being hit and miss, more miss than hit. PP's have a good rep overall and while I've only been impressed with a couple I've seen, they seem to be very consistent. WPG's and Weims are the worst of the versatile breeds, that I have seen and been around personally, not sure what the issue is, but I've yet to watch a good WPG or Weim work, so I would avoid them. The Italian breeds are interesting, I've only been around a couple, but they are generally VERY close working dogs and not what I think most folks are after. Britts are great, but water work isn't all that common for the breed, so again, do your homework.