meego takes 6 months to get new version and there's huge resources being invested, what do you expect from nitdroid team! I would say donate them some money if you want to se faster development.
Just to help answer the question.
Nitdroid uses codes from several sources that may be compatible with the N900. The fact that they started with froyo puts them at an immediate disadvantage (since there are less devices with official froyo than eclair).
But it is commendable that they did opt for Froyo so that the Nitdroid project wont be "obsolete" anytime soon.
What there eagerly waiting is for the official Motorola Milestone (2.2) update. It should arrive sometime in January (and get gutted in February). So come Feb 2011, I think the Nitdroid project will advance quite a bit http://www.nitdroid.com/index.php?title=N900
from these I think you can expect Wifi, phone, accelorometre completed.
And also propably an advance in front camera (evo/epic sources), back camera (low quality), proximity sensor, fm reciever.
These are speculative, but not unrealistic projections. If these get sorted and packaged into a build that is responsive, stable, decent battery life, safely flashed and overclocked ... I see it as a viable OS for everyday use (nearly there!)
i aint tried it yet, but I think I will with the next release