I don't think there's a good reason why they don't load for you. It's probably just a minor change to the project file to fix it. If we open up a project file that loads and one that doesn't there's a couple of noticeable differences but not many.
The first difference I noticed was the
ToolsVersion. Maybe try changing that to 14 and see what happens?
Could you have a play with it and see if you can get them to work then report back here with what changes you had to make. I suspect it won't be much.
I'm generally a big fan of Jetbrains products. I don't think I could live without Resharper. I tried Rider in the EAP for a bit and it looks awesome but I found it a little too immature. I mean, that's to be expected I guess but I'm not currently using it.