A couple of things that I would want to ascertain before plunking down my money for a course:
1) Instructor to student ratio. If the instructor is trying to manage the course by himself and there are more than 6 students you probably aren't going to get much individualized instruction. Watchin 3 shooters and correcting problems as you see them is just about all the span of control I think is reasonable for an instructor/coach.
2) Breadth of instruction. What is the skill level the course is designed for and taught to. If you just bought your first AR and need a basic course it may not be the best utilization of your money to drop 350 - 500 dollars on a two-day course from a nationally known trainer when you can get essentially the same instruction from a local source much cheaper. The savings will allow you to take a more advanced course from a nationally known instructor a little quicker than you might otherwise be able to.
3) Pace of instruction. Kind of related to breadth of instruction. One way to get an idea on pace of instruction might be round count. If you are firing 500 rounds a day the class may be too fast paced for some shooters to get full benefit. There is a balance between firing reps just to fire reps and firing reps with coaching/instruction between reps as needed. These are two entirely different things. On the same topic, does the instructor allow time for you to ask questions, or for the instructor to provide an AAR covering the points covered in the drill before you move on to the next phase of instruction.
Those are some of the things that I've learned through experience both attending courses and designing and conducting courses as a lead instructor.
One of the courses I most looked forward to attending as a young instructor was an auto pistol course conducted at a facility that will go unnamed. We shot right at 800-900 rounds a day. I had arrived fairly competent and left having added a smidgen more speed and with a certificate. The guy who shot next to me all week wasn't as prepared, he had a problem with grip and trigger control. He was still having the same problem with grip and trigger control when he left, with a certificate, only his problems were more ingrained. I learned more about how not to teach a course than I learned about running an auto-pistol that week. Lesson leaqrned - if you are going to feed folks from a fire hose, make sure they are ready to drink and adjust the water pressure accordingly.