I am just now upgrading to Leopard. It's arriving friday. But I've been using Backup with .Mac for quite a while. Actually, I use Backup with .Mac and an HD attached to my Airport Extreme BS. Redundancy. :)

I don't plan on using Time Machine because Apple ruined it. Last year they said it would work with network drives. They were so excited about this, they created AirDisk and all that. Even now, the new AEBS with HD seems tailor made for Time Machine. But a funny thing happened on the way to Gold Master. Leopard crippled Time Machine. Promise broken.

That said, Backup.app is well designed. It allows you to set up multiple backup sets that run automatically and/or manually. You can backup critical data to .Mac and more general+critical data to a local network drive, for example. This is what I do. Combine with .Mac's ability to sync your mail, ical, address book, safari bookmarks and settings automatically between multiple machines, and you are protecting most of your data.

It is not meant to be a full drive backup utility. If you want to completely clone your drive, well, do that. CCC is a great product I use monthly to clone my current system (also before I upgrade major components). It's not automatic, but so what? Most people care about their data.

Time Machine looks cool. You can find deleted things. But it's eye candy right now. Maybe by 10.5.5 it will actually be worth using it?

I'm getting Leopard because of Front Row 2, which now supports Video_TS, network shares, and other features making it a full featured, networkable, multi-media PC interface for the Mac.