Just saw it this afternoon. I would say the critics are about right. 3D-wise, I'd still say Avatar is a touch above but only because it's mostly CG. Hugo had to be shot with a real camera that gets everything right at the time of the performance. Avatar used primarily a virtual camera.
Hugo is how to do 3D right without taking $200M or tons of CG cheats to do it.
That said, it was an incredible looking 3D film and I'm so happy that 3D is gaining acceptance as an artistic tool. I mean, don't get me wrong, I like the popcorn action movies (that are shot native), but so far there haven't been many aside from CG toons that have been real, you know, Oscar-worthy films.