I'm not in the market to purchase but hope to be in the next several months (can someone say wedding gift? ). What are the opinions on the various Omega Speedmaster Professional models?
1) 3570.50 --> hesalite crystal, steel back
2) 3572.50 (discontinued) --> hesalite crystal, sapphire display back
3) 3573.50 --> sapphire crystal, sapphire display back
4) 3592.50 --> hesalite crystal, sapphire display back (gold gilt movt.)