It is annoying how expensive NAS devices are (without hard drives)
For many, you can build a PC that will support more drives, the same raid methods, and have significantly better performance and offer more features, all for much less money than a dedicated NAS.
for example, on an old system that I use as a NAS/ server/ DLNA/ game server/ torrent box (sometimes performing many of those functions at the same time) the AMD 64 3200+ system, can read and write to an encrypted partition at around 110MB/s (max speed of the 7200RPM drive)
If I want the transfer to also be encrypted, then I can SSH into the device and perform the transfer and the speeds will still be about the same.
I mainly use the DLNA function for streaming media to my tablet (since no transcoding is needed (tablet supports pretty much all of the popular formats as well as soft subtitles)
I can usually have a backup going while at the same time downloading a torrent, and hosting a left 4 dead 2 server
and still have the backup go at around 100MB/s + (I have multiple hard drives, but I did not set up raid )
The CPU rarely clocks up to it's full speed.
Not sure about the load power of that NAS box but I am sure that the old PC uses more power, but overall, it does more, it offers better performance, supports 4 drives (and can be expanded if I get a cheat $12 2 port raid card, (I can add up to 4 of them) (I can also add a USB 3.0 card since a full sized pci-e slot can also support x1 cards though I will lose a standard PCI slot since I would have to install a regular PCI videocard)
I am currently building my own NAS using FreeNAS and it's really easy to re-use old hardware and PC. I would, however, like to see more open source support for the custom hardware if I don't like the OS that comes with. I know I can build my own using standard PC parts but you have to admit these guys do make them very compact, uses little power and fits anywhere.
I also been using Iomega StorCenter ix4-200d 4TB (non-cloud edition...don't get me started about not being able to hack the firmware to become cloud aware) for years and been working great. Found a way to enable telnet and hack into it's bits and glory.
A NAS can be built to be low power and still perform extremely well for less money than a prebuilt NAS.
Simple get a mini itx board and a low power CPU and a cheap case,, (on newegg, you can build a mini ITX system (minus the hard drive) for about $150
and a system like that will get you a small size, 4 sata ports, a pci-e slot, 2 memory slots.
That is enough expansion to rival and beat most NAS devices, and if you need extra sata parts, then all you need to do is get a cheap raid card
many of the newer Llano CPU's (especially the really cheap ones, have a very low power consumption especially at low loads (a mini itx based system is almost like running a laptop with a bunch more expansion ports, generally 6 USB ports, 4 sata ports, and sometimes, an esata port and some other random port)
Yes, you can build your own NAS for less $$. However, there are other benefits provided by the DS series - lower power consumption, warranty, camera support, DSM and add-on features, aesthetics, user knowledge base and forums, and your time. I guess for some of you it may be worth spending the time to put together spare parts and save some money in the short term. I submit that in the long run, most of us will actually get a better value by going with the DS. Time=money. The more $$ you earn, the more precious your time is.