Can't give out the exact copy pasted thing, but the gist is that the ring, for 8,000 GP, lets you use a slot one lower to spontaneously cast a summoning spell (in other words, a 7th level druid could use SNA III for a unicorn, but not SNA IV for anything from SNA V), the mantle, for 18,000 GP, lets you wild shape as a swift action, and the armor, for 26,175 GP, is wild armor plus a druid's vestment. The items work in a wild shape, and all three combined grant a +1 to effective wild shape level.
There are a couple of other effects, but those are the reasons you'd buy the thing. As for whether you should purchase them, just about any druid that hasn't completely removed summoning should buy the ring, because it's relatively cheap and completely amazing. The mantle is quite good, granting a useful ability that would otherwise cost two feats. The armor is bad, however, vastly overpriced for what you're getting out of the deal. Just pick up a monk's belt and cast luminous armor if you seek high AC, and don't particularly worry about wild shape uses or minor bumps in wild shape level. Don't get me wrong, that's useful stuff, but not 26,175 GP useful. It's a bit sad that optimal itemization leaves the last in the set behind, but such is the way of things.
