All in all--great.

I started using Magoosh (both the verbal and math) after I had already been using Manhattan for several months. I felt like something was missing from Manhattan--I was learning a lot but I didn't have enough practice questions to run through. Magoosh had LOTS of practice problems, and their video explanations of questions were AMAZINGLY helpful. I watched all of their lessons as well and felt like I learned a lot. My only critique is that their questions (like Manhattan's) weren't totally representative of the test questions. After I took the test for the first time, I switched to just practicing with real GMAT questions (I bought the tests & questions packs) and supplemented that with studying the lesson videos on Magoosh. I ultimately got a 690 on the GMAT, but that was from using Magoosh, GMAT practice tests and Manhattan in conjunction.