hehe yeah actually funny how you say that because Mudbox has all the same power with thier sculptiing and detailing tools, if not more intuitive and better. I really like thier interface 10 times more than zbrush cause it has more of a photoshop feel with thier layers. But yeah I would never model anything with zspheres and they dont have the useless stuff like that. However i would like to touch more on the texturing side of things which zbrush has at the moment where mudbox doesnt. if that gets implemented into mudbox Im kissing zbrush good bye unless the really make some changes. ruining the smoothing tool really annoyed me
Mudbox feels a bit smoother(sorry…) to use but there are things in Zbrush I would like to keep like the transpose tools. I use them alot to clean up my own mess and for creative thinking. Zapplink looks great too but I haven´t been able to try it yet.
No word about Mudbox 2 so I guess it is one year away or so. Makes the choice easier for me.
I did one final atempt with the smoothbrush using a script/plugin. It made it pretty ok and I only start it up once when I start Zbrush. But they really really should warn the demo users about this. Without this my work looks like the work of a 4 year old. I would never have touched Zbrush again if this was my first time with it. When I first tried 3.0 I just sat there with a huge smile creating the good stuff from the start. No learning this and that curve and number settings writing them down on post-it notes…
When you try a demo you won´t spend a week trying to adapt, you uninstall. Enough ranting, I got it to work ok after countless hours of frustration and mad screams echoing through the corridors. Now I can get on with my Zbrush love relation. 
I had a relative problem when upgrading to 3.1 on the smooth brush, but I found out how to fix it.
> Click the brush menu on top, (the basic menu will not list it).
> Find it, and select. Now whats important is to select the Accucurve to get the correct smoothness you need. Also, set the Z intensity down to a 10-30.
> To save your brush in the basic menu without having to do this again you go to preferences > config > store config.
Overall, I love the upgrade. The design is more tidy and sleek, not much of a classical feel to it anymore. Plus the UI schemes look great with the updated design. 
Hope this helps!