I've only had experience with one of those programs (Wilmer) so while I can't compare it to the others I can certainly say that there was nothing I disliked about it. I learned a lot, got to assist in a lot of surgeries, had tons of patient interaction, and perfected my ophtho exams/clinical methods. You'll be on your feet from 8am to 8pm almost everyday M-F but by the end of it you'll be neck and neck with first-year residents. If you're persistent and are there longer than 4 weeks, you can usually get involved in research, too.