> It's better to host it in your own home.With the sterling reliability of the average residential ISP... For what it is worth, home runing is a viable option for many uses: I do run a server or two at home myself but important things are out in external DCs too.
> Everyone has an old computer with more storage space than you can ever afford from Dropbox
For transfers maybe, but are your really trusting an ancient box of parts long out of warranty with your long term storage?
> "Maintenance" is a bad criticism.
It isn't criticism (as it "this is bad and it is their fault because of how they've designed the product"), it is a perfectly valid concern when considering whether to run a service for yourself or pay someone else to do it for you.
> Use some stable distro and run apt-get update && apt-get upgrade once every couple of months
Remind me never to employ you as a sysadmin! There is (potentially) a lot more to it than that. what about setting up backups, monitoring those backups and testing those backups? What about connectivity: if you home connection goes down of you have a hardware failure while you are mobile who is going to fix it? If there is a fault with your physical line how long is it going to take to get people out to fix that?
You might not find those issues to be relevant to your (storage of and) access to your data, but to some people they are vitally important and need considering.
I'm actually planning to test an OwnCloud install for myself and family & friends, it looks like the feature set covers out needs quite nicely if it works well enough, but I can assure you I'm giving the above things all due consideration and I don't consider it "bad criticism" to do so (for my own data at least: friends and family will be told the service is free to use at their own risk!). I may even suggest we run an instance at work if my experiments with it go well, as we could use such a service but the nature of some of our data means that we can't trust it to 3rd party services.