Mine worked OK. (And works OK on the E75)

It's not great, as it requires some training to be most accurate. Both on your part and the phone's part. It helps me to turn on the name announcement, as it will reliably recognize you when you say the name like the TTS reads it.

Additionally, consistently selecting the correct entry from the popup list (at least for a while) helps adapt it to your voice.

It's not perfect on S60 by any means, but it's certainly useful..most of the time.