As the forum is filling with issues for several users, I wanted to add something that you can expect from the WD My Cloud - if you have some luck with your home configuration as I seem to have.
I just recently bought a My Cloud 4TB and did not really measure performance with delivered firmware 3 point sth, I saw some 40 MB/s displayed in Windows 7 when writing to My Cloud, which was better than the 30 MB/s from my previous My Book Live. So I was already happy.
After firmware upgrade to 4.00 I do get around 80 MB/s write performance and around 90 MB/s read performance. Again displayed by Windows, but roughly confirmed by looking at my watch.
I copied 92 files/36,6 GB in about 7 minutes. That is quite good performance in my opinion.
I do use Windows 7 and a AVM Fritz.box as router (German brand)
What disturbs me with this firmware upgrade are two points also mentioned at least similar by many posters here:
after firmware upgrade system was quite unresponsive for over an hour, with 1.5 TB on it BUT: for no shares I activated Mediaserving. Still processes like wdmcserver and convert had heavy activity, I can only imagine what happens if mediaserving IS active.
there was no sign THAT system was working on something - Twonky displays some progress, btsync does, Logitech Media Server does (programs I use), but nothing visible on My Cloud outside direct SSH connection - this must be improved in the future I think
I cannot use btsync anymore, WD raised the level of expertise one has to have before pimping directly on OS level a good bit, but okay, I see that this was always a goodie, and seems still possible. But bad luck for me, as I had a 3 machine setup for syncing with 2 My Book Lives of my family in remote locations, which worked quite well.
Don’t get me wrong, when searching for a solution for btsync I did read that many users cannot use My Cloud at all and there are even severe data losses, but it seems that this little machine has some potential, hopefully WD can get this more stable soon.