What do you think about those for hosting a Friendica Server?

Enough CPU speed, enough RAM (for how many users)? Anything missing?

Cubox: http://www.solid-run.com/products/cubox
SheevaPlug/DreamPlug: http://www.globalscaletechnologies.com/t-products.aspx
Raspberry Pi: http://www.raspberrypi.org/

I would love to buy one of those sooner or later and experiment with installing Friendica, but if you can tell me right away, that something is missing on one of them, that would help me a lot!