raschemmel:
...Can someone tell me why he should build either of those (as opposed to a garden variety UNO) ?
My thinking is that the FTDI can be purchased as a module on breakout (or inside the USB shell on a nice long cable). Everything else is a garden UNO and with Optiboot bootloader and the reset cap, it will work like an UNO... Just no need to deasl with 16U2 or 32U4.
Ray