I'll add confirmation on the ergonomics, ease of use, and mild recoil of the Five Seven. So those advantages should be weighed against the unfavoring comments to follow below. The PISTOL in itself seems a good fit for your situation, pending application, of course.
I'll also add confirmation of the extremely limited usefulness of the cartridge and pistol. I enjoyed it, and cannot say I regret having bought it, if nothing else for the experience with such a unique system, however, it's just not a high utility, high performance round, and in a pistol, its applications are limited. I did a lot of small game hunting with mine, but I found it to be inferior to the Taurus Raging Hornet, despite packing more rounds, and less practical than my Taurus Tracker in 17HMR. Certainly not as potent in terms of killing power as a .30carbine or .327FM. And only slightly more useful than a Keltec PMR-30 22mag...
Again, it's in a pistol instead of a revolver, as most of these others I've compared against, save the Keltec, but for hunting, the distinctions between revolver and pistol is largely moot.
For defense or tactical applications, I personally don't see any advantage, as the average civilian won't face an armoured assailant. Comparing performance on small game, expanders in the 5.7 don't kill with nearly as much authority as traditional, larger caliber pistols. I can certainly see applications for military where the average opponent would have some form of armour, but for civilians, a 9mm is a better choice.