I waited a week or two to see if there were any adverse comments on the internet. There weren't so I installed it on my iMac. No problems with the install and no problems to date after the install. This was about a month ago.
You ask is it any good? No doubt it has some new features but I am not inclined to activate them. To me, operationally, the iMac is precisely the same as it was before I performed the change.