Good advice - but not enormous amounts of fun
The Snowden leakpocalypse a few months back was the kick in the pants I needed to convince me to break my Google habit and host my own stuff. I tested it over and over again in a VM at home, and then splashed out on a VPS to actually run it off (current home circumstances prevent me from having my server at home).
About three months on, here's my experiences:
OwnCloud is a laudable effort. All open standards is definitely the future for me. The web interface is smashing, and I have very few issues with it. I've added in a Roundcube/Dovecot configuration for email and it's all ticking along nicely.
Unfortunately, the open standards ecosystem that surrounds it isn't nearly as robust as I'd like. I've been using the official OwnCloud app on my Win 7 PC to keep my local and "cloud" files in sync, and for some hilarious reason every few weeks it decides that it needs to resync all 4GB of music I have on the server. No idea why. I'm thinking of taking the music off as it hasn't displaced Spotify for my music listening, but it's a frustration nonetheless.
Getting stuff onto Android is a similar hassle. I'm using a free (with restrictions) sync app called Folder Sync to get the files I use everywhere onto my Nexuses (Nexi??) 4 and 7 and it's fairly solid but it seems to fall out of the background processes periodically and so there's day-long gaps in what should be regular syncs. Annoying, but I've not found a better app yet.
Calendar and Contacts sync to Android I've managed with CalDAV-Sync and CardDAV-Sync respectively. They cost a few quid each and again work fairly reliably, but imperfectly. I changed one contact's name on my phone and another on the tablet and only one of those changes made it to the OwnCloud contact list. It seems like bi-directional syncing is the problem, so for stability I have to only make changes on the web page. Minor but annoying.
Viewing documents in open formats (.odt and .ods from LibreOffice for the most part) works OK but not brilliantly in the web interface (it dumps all tabs into one massive scrollable page) but more surprisingly there's a shortage of open document editors for Android. They're all focused on the MS Office formats. I've had to make do with OpenDocument Reader, which as the name implies doesn't actually let you change files on the go. Poor show.
Email works beautifully through K-9, although I've had difficulty getting it to work on my desktop Thunderbird install. Not that a local client there is really necessary but it would be nice.
The biggest pain, to my mind, is the setup. Setting up a new Android phone with Google would mean putting in my Google account username and password and downloading any (and there's very few now) Google apps that don't come pre-installed on the phone. Setting up a new device on my Owncloud setup means downloading, installing and configuring individually each of those apps individually, which is an annoying time sink. That and they do need a bit of nannying as above once they are installed.
The only things I really miss from my full-on Googleness is bookmark and tab sync - Firefox just doesn't work with my OwnCloud setup and I can't be bothered to carry on trying to get it working.
For me as a techie it's been interesting setting it up and I do prefer having control of my own data destiny, but it's something I'd really struggle to recommend to a non-techie. With effort, my stuff just about works as expected. But it's still not as good as what I've stopped getting for free from Google, and I have to pay £12 a month for the privilege of a VPS. Still, it can only get better, right?