I used Princeton Review's classroom course, wanted to take
MGMAT but couldn't make it fit into my work schedule.
I found PR to be pretty average. My class only had 5 people in it, so I was expecting a lot of catered instruction, and I made it clear to the instructor that I wanted to score 700+. What really turned me off was my instructor hadn't taken an actual GMAT in years, and couldn't even remember what her score was! IMO, if you are teaching a GMAT Prep class, you should be required by your parent organization to sit and take the REAL GMAT on a recurring basis (I really don't care how often, perhaps once a year?), in order to stay on the up and up with the latest trends on the test! I guarantee things are somewhat different now than they were when she took the test. This is why I wanted
MGMAT, where all instructors score 760+ and take the exam frequently.
PR was designed for someone looking to score 550-650, definitely not 700+. While they have resources and advanced drills to help people with those goals, it's just not the same as having a living instructor who engages with you regularly to help you through the process of reaching a 90th percentile score. After all, that's why you're paying $1000+ for the class instead of $25 for an advanced quant book or SC guide.
I ended up scoring a 750 on the real GMAT, but I attribute this primarily to the exhaustive prep I did on my own, (200-300 hours over 4 months) using all the
MGMAT books and OGs plus supplementary OGs, plus some
GMAT Club tests.
On the whole, I wouldn't recommend PR if you can go for
MGMAT's class (even the online one, which I have seen and the format is essentially just as good as being there in real life). PR was ok for some basics and study techniques, but I think you can get more from your money elsewhere.