You'll also want to get Slay the PE and make sure you buy the solutions. Slay the PE has a similar level of difficulty that you will encounter during exam day. That, combined with the NCEES practice exam(s), and you'll be well on your way to better practice problems. Engineering Pro Guide does topics very well but the difficulty of the questions isn't too high. As I was doing practice tests, I would flag a topic that I had trouble with and re-do those questions in the MERM.
Passed Mech TFS. Had to bubble in approx. 5 straight guesses. Huge thank you to everybody on this board for keeping me sane during these past few weeks and especially to those that gave study tips. Followed the advice to get a first time pass.