A safe bet

You can't go wrong with e-GMAT. The course is comprehensive, the analysis tools are highly useful, and the questions are great at highlighting where your weaknesses lie when you get them wrong.

The quant course is pretty much perfect. It's comprehensive, has extensive material and practice questions on all relevant topics, and the difficulty levels are pretty much the same as those of the real GMAT. On top of that, the analysis tools time every question individually and collect data for average and benchmark times, so if you think you might have trouble with timing on the real GMAT, the quant course is perfect for you. I went from 44 (48%) to 50 (86%), and probably would have scored 51 if I hadn't misread a I II III question in a hurry (those questions are my bane, on one of my real GMAT attempts I identified the correct answer to be "2 only", but chose "II only" before remembering to check what those statements actually said).

The verbal course is very good. The only imperfection is that the writing style is a little bit different from the GMAT's, but that can be easily remedied by doing only official questions after you've learned all the material in the course and have about a week before your exam. I didn't actually improve my official score at all in verbal after having done the course, because I apparently screwed up a bunch of critical reasoning questions (the verbal question type I have the most performance variability with), but I nonetheless think the course is great for verbal because I was scoring 45 and 47 on 5 official practice tests before the real exam (4 of which I had done more than a month and a half before, 1 of which I had never done and then scored 47 on), whereas I had been scoring consistently less than 43 on all practice exams I took before taking the course.

If you're still unsure, do the free trial. The audio quality kind of sucked the when I did it, but the format suited me and the practice questions were very useful. The audio and the rest of the media in the real course turned out to be clean and sophisticated anyway, so don't worry about that.