They were longer active intervals so more pain. I just got into riding the harder workouts recently, and have enjoyed them. There is enough (sometimes too much) recovery in many of the TR workouts I’ve done, but I’ve survived them (so far).
The VO2Max workout was what I feared the most, and yet it actually seemed easy. So, as many others have said, it’s up to the individual. I used to ride with a guy that could pull into the wind all day long. He was large too, so we would all ‘hide’ behind him, and he was no semipro rider. He just cranked at riding that way. He had no idea why, he said he was ‘just made for that’, but I think people can improve.