"More Professional" using gmail ?
no the "pro" thing is to have an email that is on a domain that you or your business owns.
not gmail or hot mail or any of the other domains.
now you might use a gmail or Hotmail or other server to handle the smtp / pop / imap stuff but that should not be shown on your emails to customers.
to me that is much like the amateur sending a mass email via CC and not knowing to use BCC.