Applications were nerve racking, but I felt like I had control over it and it didn't take as many hours of my time. The MCAT pretty much ate my summer. I skipped family vacations, and studied nearly every day. I was flat out burnt after the MCAT.
I did them both at the same time. I would say MCAT was the worst part because the AMCAS application was prepared slowly over time (PS, LORs,
ECs, etc.) and just copied and pasted. Once the MCAT was over, secondaries were a breeze.