just $15 difference, of course go retail even you don't use that hsf.
you get a protection box for shipping by mail if you want to sell it or give it to someone later.
oem has no warranty at all,
if you burn or damage the cpu,
do you think the seller will warrant it anyway?
however, with AE Blue purchase protection, it seems to be worry-free now for buying oem cpu,
just let AE eats it in case.
if you don't overclock, get retail, $15 aftermarket hsf may not be good as the retail one.