There are lots of mount adapters available: official Sony A-mount adapters, unofficial A-mount adapters, third-party adapters for Leica, Nikon, Canon, M42... and so on but
they are all manual focus only
There's some hope that Sony will enable autofocus with their adapter though perhaps/probably just for SAM/SSM drive lenses.
Re. image quality: This is unlike any compact camera I've ever used. The images scream SLR not compact. The ISO quality is superb... easily beating the a200 (which admittedly is getting on a bit). Until Sony give me an a7xx the NEX will be my go-to camera for everything that doesn't warrant the 70-300G! The a200 has been feeling a bit neglected recently