I have used Bacula since about v2.0 with the following tape libraries: Dell PowerVault 128t (SCSI, one LTO-1 drive, 20 slots), SpectraLogic T120 (SCSI, two LTO-3 drives, 50 slots), IBM TS3310 (SAS, three LTO-4 drives, 116 slots). No hw-related problems except my current performance problems with the LTO-4 drives.
Some notes I wrote about installing Bacula on EL5: http://yalb.net/?p=130
Some relevant threads about LTO-4 performance: http://episteme.arstechnica.com/eve/forums/a/tpc/f/833003030931/m/548000932931
Some relevant bacula-users threads: http://article.gmane.org/gmane.comp.bacula.user/44565/match=lto+4