Just picked up a new Titan wheelset and...(please bear with my terminology)...it seems like the freehub (grey thing protruding from rear hub) is grinding against the actual black hub. I have yet to throw a casette on or ride them but it's bad enough that I can get the wheel to spin backwards by moving the freehub in a way in which it should freewheel. Sorry it's hard to explain. Like, when I hold the wheel by the outsides (where the QR skewers will go) the thing spins forever and is very quiet and very pleasing but the freehub (grey thing) seems to have enough friction that it rotates with the wheel and hold on to it as if I was freewheeling, the wheel slows down rather quickly and it makes a soft grinding noise.
Not to familiar with the brand but I'd get a second opinion by a mechanic (by feel only).... if the freehub bearing is stiff or the body is mounted incorrectly you want to know for sure before you take it back to where you bought it to get a replacement .... some brands have very loud mechanisms ... like ringle .... but if there is a grinding feeling, get it checked out or replaced under warranty.