Downloaded MS SAPI 5.1 and have been playing with it a few hours. Its incredibly easy to use works great. Problem is that the voices pretty much suck. Pitch, Rate, and Volume aside, I'm unaware of any ways to adjust these voices. I've been surfing around and found other engines with very realistic sounding voices.
What I'm wondering is what Speech engines anyone out there might suggest. Where might I find additional voices for the MS SAPI or where would I find another good API with better voices available? I'm willing to pay for it if its good (though not a fortune) but I'd like to test it out first.