It seems that a lot of manufacturers are jumping on the 5.7x28mm handgun train these days even as ammunition isn't as readily available as 9mm or 5.56mm/.223 Rem. The first mainstream offering was the FN Five.seveN handgun and their PS90 rifle. The 5.7x28mm round provides a high velocity for shorter range targets with a higher capacity low weight package. The Five.seveN handgun has been around for a while and hung on while other offerings dwindled leaving it to be the only real mainstream offering...until recently. Ruger jumped in with the Ruger-57 and Keltec came up with their P50, although the later takes the PS90 rifle magazines so it's a bit larger than a traditional handgun. With the new Smith and Wesson offering we now have a 3rd mainstream choice and a compelling one at that.
FN makes a great product, but they always come with a great pricetag and sometimes strange ergonomics. The Ruger and Smih & Wesson bring the pricepoints down and also give you the ergonomics you are accustomed to with the perspective brands and for a lot of people this will be welcomed option.
With an MSRP of just $699.00, the M&P 5.7 will have about everything you could want. It features an ambidextrous slide stop, reversible mag release, a slide cut to install a red dot optic, a threaded barrel, and picatinny accessory rail. In the box you will also find two 22rd magazines. It's truly the every man's 5.7 handgun and it's priced very well considering the features and backing of the Smith & Wesson name.
There is no "Perfect Round" and the 5.7 is no exception. The real downside is the inability to reach out to longer ranges and the cost per round comapred to 9mm. In a handgun at 50-75 yards or a SBR/rifle at up to about 150-175 yards you will have a zipply and flat shooting round, but after that it loses a lot of energy and does so quickly. Most people (including police) don't shoot their handguns past 50 yards or their compact rifles past 100 yards that often. For the majority, the 5.7x28mm round will be a pleasant experience if you can source a good supply of ammunition and don't mind paying for it. If you can overcome those two obstacles you will probably love taking your 5.7x28mm gun to the range.