We've stayed at a few: Montauk Yacht Club, Star Island Marina, Gone Fishing Marina, and Montauk Marine Basin. Each are different, but here is the bottom line.
MYC - great place, shuttle bus, pool, bar, restaurant, most expensive place to stay.
Star - pool, bar, shuttle, shark tourney.
Gone Fishing - no pool, good restaurant/bar, a true fishing marina, great people, no direct access to the action on the other side, least expensive. Good place to bring a bike.
MMB - fishing marina, can walk to Gossman's Dock/restaurants, no pool, cab to town (or walk to MYC and pretend you are a guest there), reasonable cost.
Sometimes we take our lawn chairs to the beach. Sometimes we take our bikes and go to the lighthouse and into town. Cool bar near the beach, sometimes they have music - don't recall the name. Plenty of good restaurants. Never stayed on the hook - believe it can be shallow in the pond.