For me personally, I get the best arrow alignment and accuracy with one of Scott Teaschner's tabs, followed by the Eichler tab from 3R and third by a Saunders Pak Tab.
The first two are Cordovan, the Saunders rubber, but all three are just the right thickness, and provide good finger protection. I've tried almost every tab available, including the Cavalier, Soma Fivics, Black Widow, Batemans, etc. Scott's tab gives me the option of changing finger ring size to suit barehanded or with a glove on in colder weather. Most of the other tabs put the string too far outside of where it needed to be...and arrows always headed left. Just my experiences.