I want to purchase gate overflow and go classes test series but only have budget for one. Which one should I choose? (Answers from people who have enrolled in the test series would be appreciated)

Answer 1

Both are equally good. 
https://gateoverflow.in/blog/14987/gate-overflow-and-go-classes-test-series-gate-cse-2024

You fill find schedule and types of tests in the above link. Go through it and decide which one suits your requirement