Sigma 8mm f/3.5 version. Do not buy an older f4.0 version.
Sigma Fisheye is superior to Peleng in every way (except price!)
Yes, no need for auto focus (but still handy). Also when you have electrical contact with camera you pass on correct EXIF information.
Samyang make very good manual lenses. But no electrical contact with (most) of their range. Also no circular fisheye available (unless like me you have modified one). Typically Samyang fisheyes are 180 diagonal full frame (much like your 10-17mm fisheye).
The Sigma 8mm is the correct choice overall if you want to minimise the amount of shots on an APS-C sensor camera.