Re: Uploads
"I suspect one of the limiting factors for unlimited space usage is upload bandwidth."
I don't think it's going to matter, that is, "all you can eat" deals are designed to give you more than you could possibly eat, with the attraction of "unlimited" being a mere drawcard, not an actual offer.
I did some sums some time back when the backup to cloud issue came up with an aquaintance who thought it a great idea.
I worked out, with my current ISP, it would take about a year to get what I have now up there. That's based on my actual speed upload bandwidth (about 14Kb/s), my actual allowed longer term upload bandwidth (half of the max speed they give me), and my total data (about 7.5Tb or so), and the fact, I will not have my full upload bandwidth capability available for general use for the next year (or, assuming I don't piss off my ISP in the meantime...),
Sending them a few drives would be a better proposition. Many cloud storage services offer this as a service, I'm willing to bet one of them is not Microsoft for this particular product.
Ergo, you'll never eat what they're "selling".