I have and use Pogoplug, so I can tell you a little about it. I have a PP device which I have two drives attached to. I also have their unlimited cloud. The device and drive acts somewhat like a My Cloud, as I can access files on it from home or through the internet. I can also access the unlimited cloud the same ways. Much of my media is on the hard drives, but I also have backed up some of it to the cloud.
Pogoplug has apps for mobile devices for accessing and streaming the media to the mobile device similar to what the My Cloud has.
What I think is different is that the My Cloud is connected to the network, and has a drive inside, but it likely is similar to a PP device and external drives. So, once your My Coud is on your network and all set up, and if you had a Pogoplug unlimited cloud,.you should be able to direct PP to backup the folders you want on your My Cloud to your PP virtual cloud. I know I can do this with drives I have on my network if I wanted to, but don’t because the PC would need to be on. Not necessary with a PP device w/drives or a My Cloud, because they are always to be left on.
You might want to set up a free PP account and get the free 5GB cloud to test and try things out. Also, once you have the account you will likely receive one of their emails promoting the unlimited cloud for $39 (instead of $99).
You also might need to know that using a virtual cloud takes good internet bandwidth. As you may know, even if you have very fast downloads, your ISP doesn’t give very fast uploads. So, things can go quite slow compared to speeds within a home network.
Hope I have given you some basic info you can use. Good luck.