Well I have PLENTY of thoughts on the subject, far too many to list here. Let me say that I have spent several years at both programs, and currently I am at CHOC, and I am SO happy here.
There are many differences, and they coorilate with different learning styles. I agree with a previous comment that you should interview and/or rotate at both programs and decide how you learn better.
First off, in medical school I realized the difference between Night Float and Q4 call, but I thought the 2 were a wash when it came to the For-and-Against columns when ranking residency programs, and i wasn't going to let it weigh in on my decision. Let me tell you - I am so happy (and lucky) that I picked a program with Q4call - because I realized that, with the way I learn, my best learning takes place in the post-call rounding. I really like presenting (or letting my intern present) the patients we've admitted overnight. I like the discussions that follow. I like putting myself out there describing what I did to manage the pt in the middle of the night, and watching the attending review all the info, examine the pt, and then comming up with his own assesment. It solidifies my decisions overnight (either to ammend my thinking or to continue with the same). I couldn't get this, the learning i"m getting now, at a night float system. Again, this is my way of learning, and it's something you need to realize about yourself. In terms of autonomy - i am very rarely calling consults while I am on call - and since I get to round post call - the pt i admitted is MY pt, ownership of a pt is a great part of learning. I'm not sure what program asks for more consults, but even on those that we do have consults on, I feel very involved in the decision making (often the specialist is asking me what I want to do - and uses it as a teaching point).
Also - I wanted to be in a higher volume place (again, the way I learn - are you seeing a pattern yet?). I definately learn by seeing and doing, and I wanted to see a lot and get to do a lot - and CHOC is perfectly living up to that. I somewhat disagree with one of the last commenters - even though we are busy, by no means does that mean there isn't time to read. I read up on just about every pt I admit overnight.
About the work hours - what was said earlier is also untrue. We have no problems keeping within our work hours - I know this because we just had the review last year. - I think the previous writer might have noticed a lot of attention paid to the "hours" issue, and figured it must be because we are not compliant. The truth is, our Residency Director feels so strongly about the 80hour rule, that he is constantly checking in to make sure we are doing fine. There are plenty of safetynets built to protect the ward residents to assure their compliance, and his regular "check-ins" are to see if he needs to use these safety nets.
Lastly - the family that is at CHOC is ultimately what made this my #1 choice when ranking. It is neat to work at a hospital where you are the only residents. Your picture is plastered throught the hospital. Everybody knows you from the nursing assistants, to the Surgery attendings. (one of my favorite stories happened my intern year. It was about 3am on a Sunday - i was writing orders on a new admit. The head Surgeon sat down next to me, he had to come in to do an appy in the middle of the night. He sat down right next to me and said "so how's your night going, are you enjoying your intern year?" - I think i peed my pants a little. First of all - how did he know my name. Secondly - YOU ARE THE HEAD SURGEON, YOU HAD TO COME IN AT 3am ON A WEEKEND - SHOUDLN"T YOU BE YELLING AT SOMEONE?- and you are taking the time to CHECK IN WITH ME TO SEE HOW I"M LIKING MY RESIDENCY!! - it is definaly a very warm environment. I feel very close to my fellow residents, and also very close to all of the attendings, and regularly sit and discuss with the attendings on a interpersonal level (i don't know what the previous writer was describing when stating that they seem stand-off-ish).
I think wherever you go in peds you will find commonalities. It is very rewarding to toil the night away to try and help a child feel healthy by the morning. - For this reason we work in the BEST field of medicine, bar none. Pediatric attendings are always going to be more kind than any other specialty (honestly, can you imagine your Internist attending wearing cartoon ties every day?) - Wherever you go you will work hard as a resident - but the learning curve is so steep, and so valuable - and like I said before, what better thing is there to work so hard for, but for the health of a child!.
Good luck each of you during your applications/interview/list-making processes.