The actual drawback I noticed only after 2 days. The mouse is very small, I did not really know where I should put my ring finger and in addition to my wrist started to hurt.
In the software I can not rummeckern actually. It is quite clear. At Synapse 2.0 I do not say anything, everyone should have their own opinion whether it is really necessary or not.
I have returned the mouse in the end and for the great service from Amazon, I would give it 5 stars. Without problems and really quick Amazon has paid the money back.
Conclusion: The mouse may be really great for people with smaller hands, but I would advise people with large hands to be careful, this should perhaps first look in a store if it is really something for you.