Few quick noticeable differences of these little cranks. I switched from 165 to 155 (Carelton's pic above) few seasons ago:
* Higher peak cadence (20-25rpm net gain).
* Higher saddle height; more aerodynamic position.
* Higher effective gear (old 92" becomes 95-96" roughly).
* The need to reglue chainring bolts every 2-3 months!
It boils down to personal preference after everything is said and done. However, metrics tend not to lie. Hope this helps!