I've been running an R5 for going on 8 years now. It has served as an excellent platform for my NAS and I do highly recommend it. It has come to the end of the road for me though (I have too many drives), so I'm upgrading to the Fractal Meshify 2XL.
As for cheap hardware, ebay. No kidding. I bought a super micro X8SIL-F mini atx board, an Intel X3470, 16gb ECC DDR3 ram, as well as a LSI 8 port SAS SATA HBA with some SAS to SATA cables for around $170. I did have to exchange some memory after they failed a memtest, but other than that no issues.
I use nano and geany at home. Both simple to use.
At work it's jetbrains because that's my only option besides notepad++