io53:
I'd rather use my PI if I need Ethernet, and unlike Nick Gammon I've had no problem installing linux on it. Tho that might have something to do with that I've been using Linux now for the last 10 years or so.
I got it installed in the end, but when the main downloads page (http://www.raspberrypi.org/downloads) lists four suggested operating systems variants, it makes things a bit harder. And then (although I have been using Linux for a while too) I had trouble even copying the operating system onto the SD card in such a way that it would boot. I did it, but it took a day.
Then when it booted, as I recall, the monitor wouldn't start up. More reading of forum pages and I had to edit a text file on the SD card to set the "voltage levels" for the video card or some damn thing.
Let me put it this way, the Arduino was easier to set up. 