A framing nailer will shoot 16's, (3 1/4") down to 6's (2") good for general construction, 2x, sheathing, pallets , etc. 16 gauge nailers shoot 2 1/2" finish nails, but do leave a pretty big hole- OK for tract houses. 18 gauge brad nailers shoot -2" finish nails,then you go to the fine finish guns- for furniture. The 23 gauge are real treat-with stainless steel headless pins it is astounding what a guy can nail without splitting- tiny little work.
In a wood shop, one of the unsung used of a nailer or stapler is to make rapid , one time use jigs and fixtures.
A framing nailer is heavy, it has too be or the recoil would break you. The nice thing is there is little shock- framers elbow in painful and takes a long time to recover from.
And ditto the ear and eye protection- those nails can come out at strange angles- do not hold near where you are nailing- they can bend into a U and come out next to where they went in.