I prefer a side button, my two favorites are the Poldiac and the Roller. The Roller button sticks out and it is a telescoping mod so you probably won't like it but the Poldiac button is flush, magnetic and comes in your choice of battery size. They are over $100 but well worth it.
I second this the Poldiac button is flush has a locking sleeve although I never have had to use them and I pocket carry every day. The button is magnetic and is very smooth and requires barely any effort further it is not your pinky. More than $100 but they are sometimes on the classifieds