I remember reading an interview with Ari Jaaksi a few months ago where he stated that Meego will have very different UI's for different manufacturers (like with Symbian). He also stated that Nokia will integrate all of its Ovi Services into the OS.

I'm guessing that this Meego release is using the basic UI. Most probably any new Nokia Meego device will look very different. Only negative is that probably the N900 will never get to experience the any UI changes by Nokia.