Hi HappyGirl101 -

Thanks for your message, I had not yet explored the Voice Dial/Voice Tag feature on my 8125. So...I tried it out tonight, and here is what I found out!
Microphone -
Bottom line, the microphone words well in terms of recording your Voice Tag and then matching the repeated voice to the Voice Tag recorded. The microphone WORKS great! But doesn't sound THAT GREAT when you replay your own voice tags, not that it really matters for voice tags, in terms of music or video, I have not tried the mic.

Speakerphone -
Works fine, volume is good and it's easy to turn on during a call by just touching the screen.

Note - Good News!
I have been having some difficulty navigating the programs/start menu/today screen etc...requiring me to need use of the stylus for 'two clicks' and not needed the stylus for the first two manuevers. Thanks to your question, I also discovered that you can add Voice Tags to programs, so for example, I can now press the voice command button, say "Excel" and MS Excel Mobile will open on the screen. Thanks for your note, led to me figuring a little bit more out about my new gadget!