This is tempting me to ignore (most of) them, use JS, but (of course) rely on server-side validation.
I am not advising anyone to ignore HTML5, I was merely reflecting my own experience. I am happy to adjust my statement to "dont count on them" if it helps
What I will continue to do is to apply HTML5 attributes, and test in different browsers. I will probably need to tweak some css. If I'm still not happy with the look and/or behaviour I might remove some of the HTML5 attributes.
On reflection, I should have said "some of.." rather than "most of.."