The Microsoft Sculpt Ergonomic mouse is semi-vertical (this might depend on how you hold it) and tracks better than the Evoluent mouse I was using before, altho

The Microsoft Sculpt Ergonomic mouse is semi-vertical (this might depend on how you hold it) and tracks better than the Evoluent mouse I was using before, although the ergonomics are probably not as good. The build quality is also better IMO than the Anker / Sharkk vertical mice popular on Amazon. Haven't tried the DXT mouse mentioned in the other comment.