I gave up on Mootools when it became obvious that the community surrounding it was much busier condescending new users than helping them. Combine that with documentation that is severely lacking and the aggravation saved by simply dealing with the more community friendly jQuery saved my sanity and time.
I made the switch about a year ago and haven't looked back since.
Wouldn't work for people behind a corporate firewall. My old employer used to route all of its traffic through the head office in the US even though we were in Canada.
I made the switch about a year ago and haven't looked back since.