Framing nail guns come in all shapes and sizes, but they all have one main thing in common, they are designed to drive larger 8d, 10d, and 12d nails into 2×4 and larger dimension wood. They are the workhorse of any framing crews tool box and using the right gun can save a lot of time and expense. I have used Bostitch, Ridgid, Hitachi and Porter Cable and Ridgid is the clear winner in my book. I have had my ridgid nailer for 5 years and it has performed flawlessly. It also has a great set of features that I really appreciate like the rear loading nail clip holder, easy nail clip lock and a swiveling air hose nipple. All of those seem like no big deal, but when you are trying to load large nails through a top loading nail gun while hanging in rafters, or move a hose around you while on a ladder to get at a tight spot, they can make the difference between madness and a job going easy. My Ridgid is also light weight made from magnesium alloy so I can drop it and not worry about breaking it.
So when considering a framing gun, make sure you look at the small details, not just the cheapest gun on the shelf, or going with a particular brand because you already have another one of their products. Failure to pay attention to features can make for a long day on the job. Good Framing!