What is wrong with Mozy Online Backup?

Well, I have an account set with Mozy for making automatic backups of my Mac. When I'm not adding new files all is very good, of course because in that case Mozy doesn't have anything to backup.
When I have new files to backup I need to send them to Mozy little by little, because sending bigger files makes Mozy almost unusable. Forget about your pictures or music!
The account I signed for is for unlimited storage, but it is very difficult to trnsfer a lot of files.
Like I mentioned in some old post, the best is to send smaller files first, then after a while send some more, and some more... while on that process be careful... you have no back up of many of your files!
I also sent to Mozy some questions they accepted to answer in the shape of an audio or video cast for this Blog... but after a few emails they send nothing anymore... probably they had no good answers to my questions... anyway I challenge them to answer because Mozy is not a bad product but needs to improve. Receiving feedback, answering questions is a way the community uses to help them.
(Mozy for Mac is stillin beta)