For the last 3 years, the Ultima has been the best thing going. It's far thinner and far more flexible than the other vests. I can't stress enough how important it is to get the lightest, thinnest, most breathable vest you possibly can.
The DOJ and NIJ stats on police officers killed are fascinating, when it comes to vests. In the last 15 years or so, NO ONE was killed from a pistol bullet penetrating a vest. Only a very few rifles have been employed to kill cops by penetrating their vests. (None of the rifle-resistant vests are concealable, BTW) The vests that save lives, week in and week out, are the vests that offer the minimum protection of a Level IIA, because those are the vests that people wear.
Richard Davis, president of Second Chance and founder of the whole concealable soft body armor movement, says "Sure, we'll sell you a super-high-rated vest that will stop anything you want. We use more Kevlar in it, and we'll make more money on each one we sell. But we'd rather sell you a light, comfortable Level II or IIA vest that will save your life, because you'll wear it.
BTW, R. Davis is a big proponent of the RKBA, and is a major gun enthusiast.