I absolutely LOVE iCloud, and I'm using every single part of it, including iTunes Match. I have now cut Google almost completely out of my life because I've switched all my mail, calendars, and contacts to iCloud and sync seamlessly with all my devices. I sold my iPad 2 so I could pay for my iPad 3 (if they ever announce it), and I love the fact that my iPad backup is sitting up in iCloud waiting to be restored to new hardware with the tap of a button.
That being said, it's not a solution for everything. I have a 3 TB external hard drive at home that is hooked up to a PC. It runs a backup every night of all my home movies, important files, pictures, etc. It's only about 5% full, but 5% of 3 TB is a lot of data. I wish there was a way to get all this stuff to iCloud as an off site backup. Right now, I'm only covered if a hard drive fails. If the house burns down, I still lose all my data except for what is on iCloud right now.
I know there are other services that do what I'm looking for, but I want something iCloud integrated. The whole rest of my life is on there now, so why can't all my old backups be there too? I think the service has been a success already, at least for me, and I would pay a fee to have more versatile storage and more of it. If you started your life out on iOS, you could probably get by just with iCloud because it's all already there, but when I was in school, got married, had kids, etc., I was still using camcorders and non-digital cameras.