Thumb-breaks are generally faster than the other retention straps that use a snap. When the thumb hits the strap, there is very little pressure needed to have it pop loose. If you try one you will most likely decide that it is what you want. They are not that great for ease of one-handed re-holstering though.
The holsters you posted seem to be well-formed to the gun, and I would say that they do not need a retention strap. However, getting a holster with a thumb-break as shown would not likely add significantly to draw speed.
Sometimes you get what you pay for, sometimes you only pay more for what you get.
Three shots are not a "group"...they are a "few".
If the Bible is the literal, infallible, unerring word of God...where are all those witches I am supposed to kill? (Exodus 22:18)
Last edited by dahermit; December 29, 2012 at 11:14 AM.