Firtst post, but i've been lurking around this board for while.
I have been using a Qnap TS-453 pro (up for sale) for the last year, and I have nothing to complain over. But the urge to build something myself and to have a bit more ooomph from the CPU did it for me. I was lucky enough to get hold a slighty tested C2750 board with 16GB ECC RAM for a good price and went ahead with my project.
My originial plan was to use Ubuntu Server or Windows as i mainly use it as a plex server. After some fiddeling with Ubuntu, I scrapped that plan en went for Xenology (bare metal), and i will never look back.
I disabled both Marwell controllers as I don't need them, disabled serial port and got going. Everything works perfect, no errors during boot and I even got 120gb SSD as cache for 2x 4TB raid0 (no need for security). I transfered 4TB from the Qnap without any issues and maxed out the GB network (110-120GB/sek)
As a complete xpenology noob I think this went very well