There are very cheap Arduino clones with CH340G chip for USB communication. Unfortunately, this chip need special driver (you can download it from vendor's web page), has documentation in Chinese only and cannot identify itself to computer via USB 3.0, so it seems as bad choice for Reprap universe.
Anyway, for applications without USB communication can serve as other clones. Personally, I have no problem with this chip on Debian Linux (both 32 and 64 bit) and USB 2.0.
Anyway, for applications without USB communication can serve as other clones. Personally, I have no problem with this chip on Debian Linux (both 32 and 64 bit) and USB 2.0.