There are many holsters, some with thumb breaks as a retention device, some with a variety of other types of retention device, some with no retention device whatsoever.
It all depends on the individual and how they will train, and how they will not train.
Personally, I can't stand thumb breaks because I draw slower with them. To each their own. I know many that love them and stand by them. If it works for them, good on them.
To call one "better" or "worse" depends on the individual and how they want to use their holster. For example, a thumb break on an appendix or lower back carry would be awkward.
I also know many that love the retention system of a Serpa Blackhawk holster. You get the same benefit of retention with a smoother draw. There are some that can't stand that type of holster too. YMMV