I’ve been playing with HTML 5 in FireFox 4 and have been pretty pleased with what I’ve found. However, some sites, like Hotmail don’t seem to work very well. Is there a way to toggle HTML 5 on and off easily?

As you say, HTML 5 support can still be flaky at times. It’s important to realise that this is an evolving standard and hasn’t been ratified yet, so it’s every user on his/her own. And you’re right, some sites work better than others.

There’s a FireFox plugin that can help called HTML5toggle that’s designed for just this purpose. Check it out.

Remember when you’re playing with new technologies there’s always a risk. You may decide to steer away for now; it’s not like you’re going to get a multiple car insurance discount for making use of it.