My business phone is Verizon. No dropped calls at all in ten years. It's always my kids on ATT that lose the connection between us.
Of course there are always exceptions, but with with everything else being equal (towers, location, etc), CDMA phones won't drop calls like GSM ones do.
CDMA by nature is usually connected to more than one tower. As you move, it uses a soft handoff technique... it connects to the next tower while still using the original. Losing a connection is almost unheard of. It also handles more people, so again, fewer drops.
GSM is only connected to one tower at a time. When you move, it does a hard handoff... it drops the current connection before it switches towers. That's when call drops happen the most.
CDMA's superiority in user and bandwidth capacity is the reason why GSM carriers used WCDMA for 3G.