I've used and tried several different boards in the price range between $30 up to $100...
Raspberry Pi has just a huge community behind, and what is best, the OS provided just works...so you can start immediately working on your small project...
Just this week I got the SAMA5D3 Xplained board from Atmel....nice board I thought...one ethernet with 10/100 and second one with GBit port....
Apparently they sell it for quite some time now...so you would think the Linux support should be in the same state as the Raspberry...
I still can't get a reliable ethernet connection from the GBit port...some times it works, most of the times not....and I am not alone...
The documentation is really poor...
Another board I tested (I tested shitloads of boards) was the Riotboard....which is backed by Element14/Farnell...
I tried to find the documentation to get a Debian image onto it, as the install process was mentioned on the Element site...
But just recently I found out the the blog post from the contributor has been deleted by Element14/Farnell....which is really great!
Community and support-wise...Raspberry Pi is a winner.....
Performance wise? Never...I rather go with i.MX6 or Jetson TK1 (o;
Ah...forgot to mention Beaglebone Black....nice little board....but after several times getting notified by Mouser that the delivery has been postponed again
made me think to switch to other boards and dumped it from my store...