Find out how many hours of instruction each course offers. Note that you do not want to count time taking proctored practice tests, just class time. A typical course offers 20 hours of LSAT review and strategy sessions.
Ask how many full-length practice tests come with the course --- you'll want five or more to get your money's worth. Make sure to ask if the tests are official exams from the Law School Admission Council (LSAC), and not tests developed by the test-prep company.
Find out how many books come with the course, as well as how much online/CD study material you will receive, if any. Often, it's the quality and quantity of written review material, not the classroom hours, that determine the cost of a prep class. Many test-prep companies actually buy material and some proprietary testing information from the test-makers.
Ask how many students are in the class, or what the upper limit is. A teacher of a large class may not have enough time to help students one on one. If you think you'll need individual attention, you may do better with private tutoring, even though it is typically more expensive than classroom courses.
Consider the length of each course and your current schedule. With any LSAT preparation class, you will get the most out of the experience if you make a commitment to attend all the classes and use all the study material. However, if you are taking a prep course very close to your test date, you likely won't have enough time to get through all of the review material. In this case, cheaper or less comprehensive courses might suit you better --- you don't want to pay for more than you can feasibly use.
After you have gathered all the information above, make a table of the different LSAT courses you are considering, as well as the pros and cons of each option. If you really struggle with a particular concept, such as setting up Logic Games, you should look for options that give you more face-time with an instructor who can teach you strategies. If your weakness is pacing, but otherwise you know how to approach the questions, you should make practice tests a priority.