The Dell CMA uses a basket that has been around for some time. This design allows the installer to shove all the cables in and be done. The bad thing is when one of the cables on the bottom has to come out. The hinges of the Dell CMA are not that strong and if an excessive amount of cables are shoved into the basket the hinges will break.
IBM uses a basket type of design similar to the Dell design. The difference is that the IBM CMA is very strong.
The HP CMA is very unique. The common issue with CMAs is that they are so deep that it can cause installation issues with the back door of a Server Rack. HP has attempted to minimize this issues by designing a very shallow CMA that mounts on either side of the Server Rack. This feature uses an overly complicated hinge assembly that is difficult to install.
Mil-Spec CMAs have to pass destructive testing. None of the OEM Rail Kits are capable of passing this demanding test. RackSolutions CMAs are built to Mil-Spec standards but not the slide rails. Mil-Spec slide rails are available through RackSolutions, but they are very expensive and are custom kits.