[Techtalk] Alternative to Dropbox

[David Sumbler]

I have used Dropbox for several years now (after recommendations from
this list!)  But only last week I discovered that the free version now
restricts the user to having no more than 3 linked devices.  Despite
this, my account details still listed almost a dozen devices, mostly
obsolete phones etc.  More importantly, it was still happily syncing my
desktop computer, my laptop, my Samsung tablet and my phone.

That has now changed: because of continual spontaneous reboots, I
decided yesterday to do a factory reset on my tablet.  Dropbox now sees
this as a new device, despite the fact that it shows the same reference
number as it does for the previous manifestation of the same device. 
Now the only way for me to get the tablet to sync Dropbox files
automatically is to deselect one of the other 3 devices that I use.

I can work around this: obviously I only use the desktop at home, and I
only use the laptop when I am away from home for a few days.  But
obviously the process of, deselecting one device, selecting the other
and then waiting for it all to sync is going to be a bit of a pain.

I could, of course, pay Dropbox the £9.99 per month they want for
allowing more than 3 linked devices; this would also give me more
storage than the 4Gb I have currently, although I have never found that
much of a problem.

I have looked at some (free) alternatives to Dropbox, but so far none
of them seem to have Dropbox's ability to keep things synchronized in
the background.  With Dropbox I don't usually need to open a web-page
or a different file browser: everything just "works" without me having
to do anything special.  All I have to do when I create a new file is
to decide whether I want it in a subfolder of my Dropbox folder or not.
And, of course, I can always change my mind about that simply by moving
the file into the appropriate directory.

I'm slightly confused by the distinctions that Wikipedia, for instance,
makes between file hosting services, synchronization software and
online backup services, so I'm not even quite sure what I am looking
for there.

Can anyone suggest an alternative to Dropbox - preferably free in both
senses - that has the convenience in use that Dropbox had for me until
yesterday?

David