Prior to getting the PSRs with vocal harmony, my duo used the digitec quite a bit. But my female singer would punch in the settings while I set up the registrations on the keyboard. This was a very workable situation. (She has since had an operation on her vocal cords and cannot sing.)

Now that I am using the PSR2K on most jobs, the Digitec has not seen the light of day.
The KB vocal harmony is not quite as good as the digitec IMHO.... but it is fine if used sparingly. But, that is also true of the Digitec.

Trying to Harmonize everything you sing is too much and not realistic. Sliding into a note will will cause a sudden shift of voices in the harmonizer which is very distractive. I much prefer to hear a singer's individual phrasing (especially in verses) and then a little harmony in the chorus when it will enhance the song.

My philosophy: The use of booze, credit cards and harmonizers should be used in moderation.

Eddie