I have the exact same one as the Ebay one. Works great. It's got a hookup for the AC clutch wire to kick the fan up a notch, a relay for the initial startup, an inline fuse, and everything you need. The Summit one is bulky and doesn't seem to have a relay...
To mount my fan and shroud, I used a fan mounting kit from a local auto parts store...basically round zip ties that stick through the radiator with a foam-tape backed plastic pad on the outside and a foam-tape pad and plastic foot that slides onto the round bit to snug it up and sandwich the fan against the radiator. Cost me $4.