I've used one (in training). Works great, nice clean cuts, but still a little slow. Quicker to just use an axe which, if you're a firefighter, you have handy. (Carefully chop around the perimeter of the windshield or side window. Use gentle blows to minimize dispersion of broken glass within the cabin.)

Expensive, and pretty bulky to carry around along with an impact driver. There are less expensive, more compact hand-operated tools, e.g.:

https://www.lifelinerescuetools.com/products/lifeline-escape...

https://www.ajaxrescuetools.com/prod-20-1-127-28/extrication...