Trying html5test.com
Best so far - Helium :

Opera-

MicroB-

As you can see, MicroB has it's problems when it comes to HTML5 rendering. It has the worst score of all N900 browsers (well, Midori scores 176, but who uses Midori?)

Fennec scores this:


Again, Fennec is almost unusable but we should aim at that level of compatibility with these standards.