Works for me. I use an MBA as my main machine and it "just works". The first backup can take many hours, so that requires some planning, but after that, not so much.
I just forced an incremental back up and it took about 120 seconds. (Not much to push, it was only 20 minutes from last automatic one.)
If you don't spend time on the network with the backup device it isn't invisible. The backups get larger and take more time. I can see you'd have trouble if you primarily used your computer away from home, but backed up at home and only used it for a few minutes a day at home.
I just forced an incremental back up and it took about 120 seconds. (Not much to push, it was only 20 minutes from last automatic one.)
If you don't spend time on the network with the backup device it isn't invisible. The backups get larger and take more time. I can see you'd have trouble if you primarily used your computer away from home, but backed up at home and only used it for a few minutes a day at home.