I still use MicroB;
Currently I still think that Fennec is not in a complete state. The problems I have with it (compared to MicroB)
- Lack of Volume Button Zoom
- Lack of Spin Zoom
- Lack of Flash (Without messing around anyway)
- Too Long to Load
- Shuts Down at Random Points
- Seems slow to me
- No Theme Support (I REALLY hate the grey)

Generally I like what I've seen so far from Fennec on N900, I just think it needed another month or so to sort out some of the above problems.