Truthfully the 2nd Gen Winch is more similar to the Revo S. The 2nd Gen Winch uses pitch/centrifugal brakes and a single piece spool shaft as does the Revo S. The STX is a dual brake and SX is magnetic only, both use the infinini II spool.
The new 3rd Gen Revo Winch is more similar to a STX in the fact that it has the dual braking, but still uses a single piece spool shaft like the S.
I use a 2nd and the new 3rd gen Winch, they both are great reels for med to deep cranking. The Gen 2 is a bigger profile and heavier reel, but if you are using it on a 7'6" - 8' deep cranking rod it does not make much difference. The Gen 3 Winch is much lighter, smaller profile, sits nice on 7ft graphite cranking rods for medium divers and such.