[ClodMaxx]

1) UE centers are titanium dogbones, and they have titanium front and back cvds... but i would recommend their hardened steel version. the titanium isn't as strong, but it is lighter. and more expensive.
2) MIP - hardened steel, but you have to worry about the pins. they aren't captive.
3) dunno... never heard of those before, but the traxxas steel cvd's look promising.

i would recommend UE cvd's all around. extremely tough stuff. i've had MIP all around, and didn't have any major problems with the front and back, but i had problem after problem with the pins flying out of MIP centers. and that's with the 'bullet proof mod', where the retaining pin has a small valley dremeled for the grub screw to set in.