Okay, FF3.1 JS is another 7x times faster than 3.0 and is already stable-ish, CSS has almost full 3.0 support and 85/100 on ACID3, so when the time comes Nokia to update MicroB, there are options available... Let's hope that's before FF4.0 comes out.

Now that i'm writing something which has to look good in MicroB, i'm seeing where the decision to adopt an alpha engine pays off.