Yep, I think it's still stressful no matter which way you are going, but the paperwork is certainly nothing to come into the US compared with going to the UK!
I am currently in San Diego, just getting started on the PETS paperwork to return to the UK (where I'm from originally) so I am already getting stressed about it. In contrast, we just had someone start at my work who moved to San Diego with her cat from Holland 2 months ago. She got a Pet Passport issued in Holland and had various records and pieces of paper with her, and as she came through customs at LAX with her cat, she was met with laughs when she offered to get out the cat's passport. "What! A passport for a cat, ha ha ha, don't be silly, just go through! Ha ha ha...." No custom checks for kitty at all!