The first off, I like the new interface for Blender 2.5. More intuitive and organized. And it runs faster than Blender 2.49_a does even with my old P4 3gigs computer with 3 megs of DDR2 ram and GForce 7900 card. The modleling is easier and smoother, both if you desire to do cube modeling or by loops or both (which I do).
I do have some problems with the new Blender 3D program, though. One is using the circle and the sphere meshs. It seems it has no way to reduce the amount of rings and segments for the sphere or reducing the amount of vertices for the circle. The only way that you can get a sphere or circle that will reduce the resolution amount is with nurbs curves and converting them to mesh. This is ok, but sometimes not what you want to do.
Another problem is with armature rigging. I had created a model and added a armature to it on the modifier list. Yet, when you click on the armature in Pose Mode and shift-click on the mesh for the weight painting process then go into weight-paint mode. But, what ever bone you click on to paint the weights on that part of the mesh you want the chosen bone to affect, it won't paint the vertices.
One more thing is that the Background image viewing would be nice if you can designate what image you would want in separate views or viewports for the Quad-View windows. Like if you have an image of a front of a person to the front view, a side image to the side view and a top image to the top view. It also would be nice for view ports for the back, bottom and opposite side. Doing it while using the left, right, up or down keys on the keypad only gives an orthographic (or perspective) user view that won't show any Background image.
All in all, Blender 2.5 is very well done, easier and quicker to use and model, really does a bang up job maintaining computer resources and has a great organized layed out.
Thanks and keep up the great work,