The leather carrying case currently being sold by Sprint may be the "official" leather case for the EVO 4G, but it's not the only that bearing the HTC brand that can be used with the handset.
Design & Quality
Unlike the slightly used look of the other leather case, this one is really soft and supple. The cushioned leather has a hint of sheen to it and is of very high quality; it makes the official leather case almost feel like old cracked vinyl in comparison.
Other than some vertical stitching around the middle, the HTC branding is the only decorative element on the case. The khaki-colored suede inner lining is visible around the edges, though that seems to be more out of necessity than design. Either way, I think it looks nice.
The sides are partially open and there's a non-removable belt clip on the back.
The belt clip rotates 90 degrees in both directions to allow you to wear the case vertically with the flap opening right-left or left-right, depending on your preference. The clip itself is tight and sometimes needs to be pulled open and guided onto a belt.
As with other leather cases, this one adds a considerable amount of bulk to the EVO. With that bulk comes a lot of protection, though, so it's give and take.
The suede lining has a lambskin-like feel to it, which makes sliding the EVO into and out of the case very easy. Some suede linings can add a bit of drag to the device, as it's "stickier," but this one isn't like that.
Two magnets keep the case securely shut and are strong enough to snap the flap down on its own. You don't have to push it all the way down yourself; after a certain point, the magnets will reach out and hold on to each other by themselves.
The high quality of the leather, clean design, easy insertion/removal, and strong magnetic closure of this case make it an attractive choice for me. Unfortunately, any case with a non-removable belt clip is an automatic no-go for me because I don't wear a belt.
But if belts are part of your everyday attire, then this case for your HTC EVO is definitely worth a look.