ADSM/TSM Configurations

I’m looking for discussion by users of IBM’s ADSM backup software (now renamed to Tivoli Storage Manager). We’re using it to back up Sun E10K’s, IBM SP2’s, and NT Servers. Yet we’re configured to run the server end on OS/390, which we’re hearing is much slower than running it on Unix. Has anyone else started with it on the mainframe and moved it to Unix? Let’s hear about your experiences with ADSM – good, bad or ugly.