You mean: I start Firefox in order to use a certain extension. It immediately updates itself and wants me to restart it, at which point I get "extension x is not compatible with this version. Checking for updates to extension - none available" - so I'm stuck for the next day or so. Has happened several times for me! At least Opera's auto updates will be free of that problem!

I don't see any problem. The key to stability is keeping your OS clean.