I have been trying to find a quick and easy way to delete backps on the NAS and by far the fastest method is to delete then recreate the network share upon which the backup(s) reside.
My domestic network is Macintosh based and deleting backups using the Finder will work but it can take days rather than minutes. This poor response points to a MBLD issue.
I am using TRI-EDRE's Tri-BACKUP Pro in preference to TM but unlike TM, Tri-BACKUP Pro keeps me fully informed of how my backups are progressing and, conversely, how quickly backups are being deleted. I am left in no doubt that there is a software design problem with the MBLD, which after almost a year I am still trying to resolve.
I think the MBLD product has a problem because it is excessively slow when handling certain requests. Identifying the problems is a real headache though.