I remember Nuance well of old - after they were borged by ScanSoft (who'd already acquired Dragon) they picked up Lernout & Hauspie when they went bust & they also bought Scotland's Rhetorical (whose superior TTS product they withdrew from their product range PDQ). The old Philips speech division is now part of Nuance too - they seem to have swallowed up virtually all competitors, so they now own the ball park in terms of commercial deployment.

But all of these large companies, now amalgamated, have thrown zillions at R&D over the years, so it's a bit unfair to even make a comparison with lil' ol' eSpeak. OK, it's not Dragon, but It's free, and it's intelligible, it'll do to get me from A to B :-)