... is that they are all teaching the same thing. What differentiates them are the quality of their study material, how they present the subject matter, and how they motivate you to prepare.
The thing is, by the time we graduate from law school we all have a pretty good grasp of the limited body of knowledge required to pass the bar exam. Because of this universal fact, the value offered by the various bar exam preparation programs comes down to how we relate to the personality and style of the person doing the tutoring. Sometimes the tutor is the person whose name is on the front door; other times the person doing the tutoring (read, motivating) is a hired gun who can present the material in a more interesting or thorough fashion.
In large part (ihmo), the degree to which you will benefit from a particular bar prep program depends on whether, and how much, you like the person doing the tutoring. It's very similar to the times in school when you really liked a particular Professor and didn't like another. You usually performed better for the Prof you liked than for the one you didn't. Sure, sometimes you were just more interested in the subject (e.g., Crim Law v. Property). But usually, your desire and ability to do well was influenced more by the medium than by the message.
Bar Prep programs are the same. Assuming all other things are equal (our grasp of the material, our desire to pass the bar exam, our ability to retain the information, lack of other disruptions/distractions in our personal lives) the key is the relationship, if you will, between the tutor and the pupil.
So, if you're looking for a tutor, you should find someone you can relate to and who can relate to you. It's a buyer's market out there. Don't commit to a particular program just because the person on the other end of the phone insists that there are a limited number of seats in their program and, hey, you're in luck because they just had a cancellation. Take some time and make a calm rational decision. Talk with the person you'll be interacting with. If something doesn't feel right, move along.
There are lots (and lots) of people in the Bar Prep business. Some of them rely only on your determination to pass the exam so you can get your license and start working. They know that you're going to pass no matter who takes your money. All they have to do is stand in front of the room and read an outline. In one program I sat through, the guest lecturer said "No questions please, I've only got 90 minutes to get through all of Civil Procedure, and that includes a 15 minute break." Unfortunately for us, the 90 minutes also included correcting the errors in the material issued to us by the author of the program 30 days prior. These people tend to inflate their image and often brag about very high, and unverifiable, pass rates.
Other tutors care about your plight and know that their future income depends on your success. They're excited, energetic, and genuinely interested in you and in your progress. Take the time to find these people. Make a few phone calls or go sit with them and talk about their program. If you do that, you'll be much more likely to have a positive Bar Prep experience, and you'll greatly increase your chances of receiving good new in November (or May).