Did you have the photo thumbnail issue that seems to affect some of the other models?
Do you have IP cameras linked to it too? Something I'm interested it but wonder whether it's worth looking into.
To be honest I don't really use it to share photos, I use it more to share video and data. I used the iTunes server for a while as well, but only have a small library so decided to keep it local.
Haven't used IP Cameras yet, but am looking to buy a Y-Cam Knight. Loads of good reviews and good night vision as well. Completely compatible with Synology, including motion detection etc, and at a reasonable price.
Bear in mind you can add one IP Camera to the unit, but have to purchase extra licenses to add more. Not sure how much they are but I don't think they are too much.
I don't think you can go wrong with either QNAP or Synology to be honest as they are both pretty flexible and you can do tons with them, not just share data. I decided to go with Synology as I preferred the interface and i read better overall reviews on the unit I decided to purchase in the end. I also liked the idea of being able to upgrade single disks to larger ones, without having to break the RAID array.
With RAID 5, for example, normally to upgrade the volume to a larger size you need to upgrade all disks to larger disks at the same time, and then restore from a backup etc. However, with SHR I can upgrade one disk at a time, if I ever need to, without any downtime, or without breaking the array at all, thus spreading the cost of upgrading to larger disks over time.
Not sure if QNAP do anything similar, but a pretty neat feature alone.
Also bear in mind they come with rear ports also. So the Ds212+ you are considering, has USB3 ports on the rear. Thus if you ever wanted to add more storage, simply get any USB3 drive and plug it into the back, and you'll get the option to either increase your current volume, or create a new volume using the external drive.
For example, I have 10TB worth of drives in my unit, which gives me just over 7TB useable space after formatting a RAID5 SHR array. I also have an external 4TB drive connected via eSATA. When I connected this drive I had the option of creating a new volume, or extending the 7TB or so I have already, after which it would all just appear as one big 11TB or so volume. I decided to use it to backup my NAS though, and have it scheduled to backup to the external drive every so often to take off site etc.
I guess what I'm saying is that the entire solution is really pretty flexible. You can set up exactly what you want pretty easily, and the support is also pretty good I hear, not that I've ever needed to use it!
It's certainly not the cheapest solution, but I, for example, can't see myself needing anything more then this NAS for many years to come!