The best, in my considered opinion, would be the Prestolite 100amp ALV series...ALV9610 I think, is the model.
Very reliable.
However, whatever you do, do NOT purchase from Kelly Aerospace...as their overhauled units are subject to failure on short notice.
Kelly is very bad news....unless of course you are after a boat anchor.
Second choice would be a TCM alternator...nearly as good as the Prestolite units.