Gunsite. Its the Harvard of shooting schools. I'm a graduate of both the 223 and 556 class. The 223 (basic) course is heavily focused on fundamentals including weapon manipulation, shooting from conventional and unconventional positions, indoor and outdoor simulators, and shooting from 0-400 yards. There is a fair amount of long range shooting, but you learn what the gun is capable of.
The advanced (556) course is focused on close range, CQB, tactics, thinking on your feet and advanced skills. We shot 14 simulators including indoor, outdoor, nightime indoor, nightime outdoor, the scrambler, urban scrambler, live (with simunitions and armed agressors), etc... This one covers just about everything including transitions, shooting on the move, extreme unconventional positions, shooting with your optic out, target discrimination, night tactics, and a whole lot of rapid shooting. However the advanced course also rewards thinking and target discrimination rather than just shooting anything you see. Only thing we did not focus on was team tactics.
The 556 course is probably the most fun I've had at a Gunsite course, but you need to master all the basics from 223 before you can shoot 556. For the 556 course we spent less than one day reviewing everything we learned in 223 and then went right into the sims. Any downtime between sims was spent teaching new advanced skills.
Get a light carbine - mine is around 6 lbs - because you will be carrying and shooting it all day every day. We had many people show up with heavy carbines with too many accessories, and they usually started shedding gear by day two. You don't need a heavy rifle. You can hit steel at 400 yards with a pencil barrel and red dot if you know what you are doing.