I came to Sage as an engineer fresh out of undergrad who wanted to get in the 700s (highest I had scored to that point was 680), and left Sage with a fantastic GMAT score (760).
First of all, I actually enjoyed going to my GMAT prep class. Insane, I know, but Sage made it an enjoyable, welcoming place to learn and collaborate with my peers. He didn't take himself too seriously, but still was able to drive home critical pieces of information. Finally, he took the time to really get to know everyone in my class, down to knowing fun facts about each person. I cannot recommend him enough as a person, and that is before anything to do with his effectiveness as a tutor.
He was well-versed in both the verbal and math sections (I needed more help on the former, some needed more help on the latter), and was able to hop into breakout rooms if anything ever got confusing. In this era of Zoom classes, he used annotations seamlessly as well. Don't worry about useless busy work either, he picks relevant problems / topics to ensure everyone does their best.
In short, I cannot recommend Sage enough for any GMAT services - great guy and great tutor!!