NIMOL lacks a lot of the features.
NIM on AIX is a lot more powerful (and easier to use).
Good thing about NIM on Linux is that you can have bootable AIX images on your laptop. Makes things easier when you have a host and network down.
NIM on AIX 5.3 also has Power5 Tools, secure comms and NIM HA.
"If you always do what you've always done, you will always be where you've always been."