I tried it , I could not open the thumb keypad, and when I want to open the small keypad and wanted to paste an URL, I was unable to paste it (the copy/paste popup showed briefly and disappeared immediately. Furthermore I could not make new bookmarks, only bookmark folders. And the letters are so small even for this hi-res screen that I cannot read them properly.
Conclusion: crap, or at least too much beta, and I uninstalled it.
I hope in future versions that these issues are solved.
A positive point is that the user interface looks intuitive and checking on sites it does luckily not use a 'mobile' user agent, MicroB does neither.
That is why I use the N810 browser rather than a browser on a phone which shows limited WAP versions of some sites.