I looks like a nice lens, but I can't see spending $200 to shave off an inch or less of my 50mm 1.8, and to lose a stop and a half? The 40mm would be a nicer length for a cropped sensor, but personally, I'd take better light gathering. The 50 1.8 is also a good performer especially at f2 - 2.2 (which is still a whole stop advantage...).
The only things that would make me really interested are: sub-$200 is really in the $150 range, and this thing is sharp at 2.8 and focuses quickly. It doesn't need to be 70-200 quick, just a decent bit faster than my 50 1.8. If it had USM, I'd be all over it. As it is, the metal mount is a definite bonus over my nifty fifty. I guess this also depends on the price of the current 50, because I got mine at a low point, for under $100, and now they can be in the $130 range, so difference isn't as big.