I have a WHS 2011 setup for media streaming and backup. Media Streaming could be done with a Win7 or Win8 machine. In many ways it would be easier to deal with a Win7 or Win8 machine. No funky dashboard to deal with (I mostly just remote into my server), just normal folders and sharing of those folders.
But for backup, WHS 2011 is pretty good. The ability to keep multiple "image based" backups for each computer and hardly use any space is really nice (because it employs data de-duplication). That said, I have run into bugs. Sometimes the backup database gets corrupted and you have to run a repair. I haven't lost anything as a result of these "repair ops" yet, but it is probably only a matter of time. That said, I have done several bare-metal restores when HDD/SSDs have failed or become corrupt. It is a bit of a PITA to get the network drivers to work when you restore, but I've always figured it out. A better scenario would be if we could export the backup we want to a USB drive and use vanilla Win7 bare-metal restore. WHS 2011 is a lot better than WHS v1 in this regard as the latter required you to hunt down Vista 32-bit drivers (the restore software was based on Vista PE environment). But if they could provide some sort of backup add-on pack for Win7/Win8, I'd be there. That, combined with storage spaces, might be pretty nice.
And the way MediaStreamingAdmin is a separate user account with an unknown password makes it difficult to see what is going on with the WMP media library, since you can't just log into that account. My media library on my WHS external website is still non-functional due to this (or some other problem). I guess there is not much chance we get any fixes to some of these issues any time soon, since the product is being abandoned. Bummed, but really all they need to do is provide for backup of home PCs to a central Win7/Win8 machine.
I feel bad for some of the ISVs that have embraced WHS 2011. Folks like MyMovies... That's a lot of dev work for nothing.