Apple now offer a ‘family’ 200GB of cloud storage
Regardless of where the data is stored and how much it costs (my "family storage" currently stands at somewhere around 2.5TB, and 90% of that is self-created media, not great scads of films, tv shows and music), the biggest downside of online storage (for me, at any rate) is the rate of access. Uploading the photos and videos from phones and cameras to my local NAS after a holiday takes long enough (recently came back from four days away with something like 40GB of new meda), but to online storage?
At present my ADSL2 uplinks at something like 1Mbit if the wind's in the right direction. 40GB would take getting on for four days to upload. If I were to upgrade to VDSL (available since last year) it looks like I'd get only 10Mbps uplink, so it'd still be an 8 or 10 hour job.
And then when I want to access the photos and videos, or my children want to make (say) a collage of memories? Something that, with media stored (near) locally, takes hardly any time at all, suddenly begins to feel like I'm back in the 1990s and dragging clipart off a dozen floppy discs(*).
Until "broadband" speeds are universally in-line with local networking speeds, purely online storage is a non-starter for me. A minimum of 100/100Mbps should be ok at the moment, though I have to note here that for reasons I needn't go into, my NAS is currently the "wrong" side of a wireless link that has a sustainable throughput of somewhere around 80 - 100Mbps and it does make some operations - for example loading thumbnails for a directory full of images - a little more frustrating than it used to be when it was wired in to the 1Gbps network.
As a backup? Hmmm... yes, so long as the backup can happen automagically in the background.
And I didn't even mention data caps...
(*)I only recently realised that one JPEG from my 9 year-old DSLR is equivalent to somewhere between two and three of the Acorn 1.6MB floppy discs I used to use every day, and one from my son's "bridge" camera would take between four and five!