It is much quieter
I am furious that the company did not tell me that a new model was imminent when I purchased mine only three months ago. I would have waited. Whilst I love my machine, I would have preferred to have been given the option not to buy one that was about to become obsolete. This has gone down like a lead balloon in the UK, where facebook pages are positively buzzing with indignation.I think the company have done themselves a great deal of damage.
So far the lower noise is the big sell for me too. However, I really dislike the fact that Vorwerk chose to use the 'chip vs. USB therefore monopolising the market so that other (excellent) recipe authors can't contribute :/ Reminds me a little of the Android v. Apple saga.
I wonder why vorwerk wasn't more upfront about the new model and decide to give potential buyers the option to get TM31 at a lower price or opt for TM 5 (rather like car yards do when a new model car comes out). Win-win for Thermomix buyers everywhere if they had done that - gets rid of old stock and no potential buyer feels cheated.