@slarti76sync of icons: it should be doable over basic sync of zip files and it probably ends like this, but I would rather discuss this with the rest of the team before I'll post some more info.
Anyway, custom icons & attachments are currently not synced, we know about it, we consider this as a limitation and will definitely work on it with higher priority as the next step.
@Andrew Heard"More info" button > well, right. More info is not really "more info". Some stats may be useful here, to see exact progress...
Duplication: hmm, there had to be something that caused this problem! Your first and second sync were from the same device? There was no restore of the old manual backup between sync?
@jonny.blueSync of the visibility: sync system is not just between the device, but also for the web platform (web planner). As @slarti76 correctly wrote, all these "devices" are most probably used for the different use-cases. Automatic sync of item visibility for the web means always load all visible data = overkill for the web. It will also cause a lot more synchronization operations because not just editing of the point/track will trigger a sync, but also it's simple change in the visibility. I see a few more problems that may come with it. So sorry, no, it is not planned and it brings a lot more negative effects than benefits.
Anyway, as usually ... time and usage in the field may reveal unexpected results/usages that were not visible from the sofa

.
@michaelbechtoldI remember this proposal well. We discussed this for quite a long internally but were not satisfied with any possible solution based on generated hash from title/content etc. So yes, we are going the way, where the first used device should be a master device (it is automatic for new users, existing users have to be a little careful) and all other devices get a choice in updated UI, if they want to keep & merge current data or want's to remove local content completely and pull data from the server.
If we prepare UI for this "flow" correctly, it should be perfectly safe and 100% accurate. I'm anyway curios, what happen to Andrew because data duplication should never happen.