There are a few basic requirements I'd use to select a duty weapon or LE sidearm;
Does it have or can it get 3 dot night sights?
Could it work well with gloves or in cold weather?
Can the semi auto pistol be used with ease with either hand(ambi features or able to convert).
Do other LE or federal agencies issue or allow it?
Does the pistol break down or be field-strip quickly w/o any tools or add-ons?(many modern or popular brands may NOT meet this standard).
Can the semi-auto pistol be used in rough conditions(snow, rain, dust, mud, etc). Safe queens are NOT good duty guns.
Do they have duty gear, holsters, spare parts, magazines, etc ready or available for the model or brand?
These are some of the points I use to buy or use a new semi-auto duty weapon.