The two main reasons I don't like it are 1) now that our Systems team handles backups/restores with the Commvault product, you have folks who are not Database Professionals attempting to master another tool in their "spare" time. And these guys don't even want to open Management Studio so they are separating themselves from Sql Server itself. I've already seen some problems from this. For example, during a conversion we switched from Full Recovery to Simple and the commvault "wizardry" automatically started a differential backup -- I guess it presumed this is what we wanted although the database was quite busy and it wasn't want we wanted.

2) It inserts a layer between the user and SQL server. The commvault commands show up in the sql log, but can be misleading -- after resuming full recovery in the scenario above, I saw log backups resume after the post-conversion full backup, but we found out the next day Commvault would not in fact restore those transaction log backups. So we went all day Monday without log backups running.

Some of this is just a training issue.