So many differences and variations especially in the early years. Omega was changing configurations yearly. You can concentrate your entire collection on Speedies and not get bored. Straight lugs, turned lugs, cal. 321, cal 861/1861/1863, applied logo on dial, painted dial, long indices, short indices, want some variation from the Moonwatch, there's the Racing models, and on and on.
Very different "feel" from the automatic models. Just my opinion though.