You took the plunge. You're sporting Sprint's and HTC's latest and greatest, and now you need to protect your newfangled investment. Let me introduce you to the Mobi Products Hard Shell Case for HTC EVO 3D. It's thin and smooth, but without sacrificing protection.
The case comes in a two-piece, snap-on design, with front and back pieces. It's simple to click together the pieces and install, but once it's on your phone, it cuddles up nice and tight, not likely to come off in the event of a drop.
There are all the standard cutouts for the various ports on your EVO 3D, as well as a fitting hole for the phone's dual cameras. Despite the overall thinness of the case, there's just enough thickness added to keep your camera lenses from sticking out from the rest of the phone. You also get a few millimeters of thickness on the front of the case, ensuring your phone's touchscreen never makes contact with anything if it's set face down.
It also features that soft-touch plastic that's become all the rage these days, so it feels good in hand as well as slides in and out of pockets (and probably purses) easily.