I've fished both, and for me fishing was better on Kensico, but that was a decade ago. In order to really do well, you need to have access to a boat. The regular crew that fishes there are notoriously tight lipped, and very skeptical of new people. I would prefer to have a boat on Croton. There are tons of rules for the ressies. I would be fishing one of the boat storage spots, and trying to meet and make friends with someone with boat access.
You could also reach out to Outcast Bass Club http://outcastbass.com/index.php?option=com_frontpage&Itemid=1
They are a solid group of guys. If you do, reach out to Dennis, "Big D." Tell him I said hey man!