I've never found synchronization to be reliable enough to want to automate/schedule it. I always have to manually test my synclist against the HH files, as MC does not synch correctly after some tagging changes. In fact, I just ran a sync, and find there is an extra file on the HH that did not get deleted, so the sync list and HH file list counts are different (Delete HH files not in sync list is enabled).
There are problems with the HH sync, for sure, but depending on your needs, you can absolutely automate it with decent results. I found that almost all of the problems were eliminated when I stopped trying to sync directly to devices, and went to an intermediary location on a regular hard disk instead.
Here's basically what I was doing:
* Sync essentially my ENTIRE library over to a folder on my computer's hard drive. For use with iTunes and iOS devices, since you have to sync using iTunes anyhow, this is your only choice. I did exclude some stuff from this list, but not much. Basically, all Music and Audiobooks.
* Imported this stuff into iTunes separately. I tried using MCiS to do this, but it does the import the "slow, dumb way" and with 66K assets or whatever I had, it would have taken weeks to complete. So, the first time, I imported manually.
* Then, I set up MCiS with the fancy iTunes File Key thing it can do to point the iTunes versions of all of my files to the handheld sync location (which, I believe, was right where iTunes looks, in the User's Music folder).
* Scheduled the Handheld sync and the MCiS sync to happen automatically twice per day. Since the big bulk conversion was already done (and those files are largely static) these syncs usually only lasted a few seconds. But, they'd automatically pick up any new stuff I'd added to my Library and sync that. I even made a nice "New Files" smartlist that would sync to the iDevices that showed what was new.
* Since MCiS enables bi-directional sync of some file metadata, I could do things like rate files on the device, and then that would eventually sync back to my MC Library. This, in practice, didn't actually help much because I found I was too lazy to actually re-sync my devices much.
It worked quite well. The main thing that would bork it up was if you moved files in MC (going by memory, but I believe that was it). Basically, if the Handheld has already synced a particular file, it WILL NOT resync it just because the Path should have changed. If the file is there, and MC determines that the file itself is "correct", it won't resync it, even if it "should" (according to the path organization rules you've defined) be in a different spot. I imagine this is an optimization to speed transfers, but it messed me up.
This stinks, as it would break the MCiS iTunes File Key thing if I moved files around after the fact in certain ways. The only way I found to work around this was to find the offending files in the iTunes "handheld" folder and delete them. This was made somewhat easier by the fact that I imported these files into MC (specially tagged so I wouldn't see duplicates everywhere), but it still was problematic.
The system was a massive pain to get set up properly and working (not for the feint of heart) but it did work reliably for more than a year before I gave it up.
At least, the MC part of it worked. iTunes on the other hand... Well, if you've done a bunch of syncing through iTunes, especially with a Library of 66K+ items? Then you know what I mean...
So...
@glynor
I'm not sure I can sufficiently read between the lines of your JRemote comment.
Are you using the app to send media to your iDevice (and store it there within the app? Is that possible?) or just using it around the house for streaming?
Why did I give it up? Well... I didn't really give it up "on purpose". I upgraded my server to Windows 8 a while back (by nuking it and re-installing from scratch) and I'd intended to set my system back up again, but I never have, and now I've decided that I don't miss it.
JRemote can stream not just on your local LAN, but if you open the appropriate firewall port on your gateway, it can stream over the Internet. I'm actually listening to music on my iPhone RIGHT NOW, streamed to my phone from my MC server at home, and I'm on 4G cellular at a weird mansion in Acadia National Park (don't ask, it isn't a fun mission).
I found, over time (prompted by laziness) that I just don't care. If LesPaul adds local caching of content to JRemote it'll be even better (as right now, my iPhone needs to be able to get online for it to work), but since I'm using a phone and iPad with cellular connectivity, this just doesn't happen very often.
Basically only when I'm going on a trip and flying, but then I generally want to sync over a few movies or whatever to the iPad anyway, and having music there would just suck up space (and I'd probably delete it before I left).
Other than that, it just hasn't been a problem. I have a small set of "emergency music" on my phone (mostly used for testing, and left over from the last sync I actually did with my old system), and I've removed the music from all of my other devices, and hidden the default Music app in a folder on the last page of apps.