On-Line storage

I'm wondering why I shouldn't consider an on-line back-up solution? As
an example, allmydata.com advertises unlimited storage for $5.00 a
month. A big external disk is on the order of $150. It would take 30
months to pay for the disk at $5.00/month. course, it would probably
be full before then.

Cons (as I see them are):
1. Personal data may not be so personal.
2. Access to files limited to download speeds.
3. Company could go out-of-business, then what?

Pros (As I see them are):
1. Unlimited (off site) storage. House burns down, data are still there.
2. Cheaper than purchasing own hardware when considering hardware's
useful lifetime.
3. Data are backed up for the user (presumably). A con if not.

For an average home user (me) the on-line solution is appealing. Am I
missing something? Any suggestions for reputable companies providing
this service?