I never tried the Amiga speech synthesizer, Totoro3D, so I can't really compare. Voice synthesis has improved in the last few years. Most of the freeware utilities aren't state-of-the-art, but you get what you pay for.

Freeware speech synthesizers:
FreeTTS 1.1
ReadPlease 2002
AnalogX SayIt v2.03
My Text to Speech (Lips)
VB Speaker
Sh*t Talker

Here's an example of AT&T's Natural Voices, lipsynced with Mimic:
Video clip (MPEG format, 537KB)

And here's a sample of a real human voice (esteemed actor Sean Connery), again lipsynced with Mimic:
Video clip (MPEG format, 334KB)