by mr 626.
I would agree with this- Chrome is certainly the 'best' of the three. Chrome is more liberal with using system resources however and I expect this is why it seems better- Chrome uses more CPU cycles etc and as a result whatever user-side operation is causing this slowness when turning editing on is more quickly dealt with (IE says its a script, but I haven't been able to verify that).
The problem I faced initially (and this is my fault for not checking)- I use mainly Chrome on my Office machine whilst my users run Firefox or IE. So for a while I wasn't seeing the problem!