I'm not sure if this will change much for end users. I'm a long time Opera user and some sites will just lock you out unless you use Chrome or FF even if Opera

I'm not sure if this will change much for end users. I'm a long time Opera user and some sites will just lock you out unless you use Chrome or FF even if Opera likely has an implementation that is more standards compliant than both browsers. Even sites like Udacity's course viewer did this (maybe they changed it, I haven't been there in a week). So while Opera might be using the same rendering engine as Chrome, you'll still get locked out because web apps are setup to investigate user agents to determine who gets in. I'm not sure if I like or dislike this change. I feel like testing sites between Opera, Chrome, FF and IE I had a better chance of eliminating all rendering bugs. Opera I feel was/is the best candidate for ensuring your code was correct.