I bought the physical copy but to be honest. I found trying to have a prop up a 5lb book was a bit annoying
Pros: - Exhaustive book covering every single math concept on the GRE -Each chapter starts with easy questions and gradually gets more difficult when you approach Q20 and above! -explanation are in the back but sometimes I had to look online for additional explainations. -Really helped me understand how I was poorly prepared and after spending a month or so studying 4-5 hours a day, My math really improved -VERY CLEARLY LAYED OUT Cons: -really heavy so looking for a solution to a problem can get annoying. - I did not care for the online service. Super annoying that you cannot advance to any lesson you want, You have to actually do the prior chapters if u want to unlock the more advanced material. - The verbal section is absolutely awful. I DO NOT RECOMMEND FOR VERBAL PRACTRICE. This book EXCELS at Math but is terrible for verbal learning in my opinion.
Overall: This book really helped me get on track and taking a chapter a day is a great approach, if you travel frequently and take your work with you, the E-book will be a much better experience than lugging around a 5 lb book when you only need to study a specific chapter. DEFINITELY RECOMMEND FOR QUANT