I bought the refurbished 6300--for the presets.
The way I was looking at it was that I wanted super simplicity for each level of person using it...distracted Mommy, clueless Daddy, disinterested babysitter, confused grandparents, and with the projected life of the machine likely also well meaning child (my oldest is 6 years old).
I just got mine today and I don't think it's all that noisy at all (less noisy than my husband's new Starbucks coffee machine). I do however have to store it with the canister beside the base and pull it out to use it because of my low cabinets. :/