I got the BikeMaster mirrors in and installed them over the weekend:
Overall, I'm pleased with them. When I first saw them, I thought they were going to be too small. The dims are similar to the stock mirrors, but since the BikeMasters are oval, you lose a good percentage of the surface area. Nonetheless, it doesn't "feel" like much was lost, and the extended length of the mounts virtually eliminated the blind spot that was bugging me.
As you can see from the photo, they do extend about 2" further out than the stock mirrors, but that 2" was more than enough (insert "That's what she said" joke).
So, I would recommend this as a good alternative to extensions for the stock mirrors - and the black finish looks really good on the bike.