Just saw this thread and since I just answered the same question via PM I'll post what I wrote on here. If you have any more questions feel free to ask and again this is simply MY opinion.
I'm more than happy to give you my opinion on how the two compare. I feel like I have some background on both as I lived in AZ for 10 years prior to coming to CCOM and I was also accepted to AZCOM. First and foremost let me emphasize this is a PERSONAL decision. Ultimately what you achieve in med school is dependent on you. That being said I do believe the rotations here at CCOM are stronger than the ones in AZ. Does this mean you can't get good rotations at AZCOM, absolutely not, Primary Childrens in Phoenix is one of the better childrens hospitals out there, but how many AZCOM students actually get to do their peds rotation there? You can get good rotations in Phx but you will have to put in a lot more legwork to figure out which ones are good and how to approach the system. I did research the rotations they offer in Ohio and they are actually at good hospitals teaching hospitals that have osteopathic residencies, however I had no desire to move to Ohio for rotations.
My decision to come here was partly based on the fact they have more clinical faculty associated with the school. For some specialties this can be helpful. Also the fact that Chicago as a whole has much more medical education opportunities than Phoenix. Doing rotations in Chicago lets me expose myself to some of the residencies I otherwise wouldn't be able to. I don't know what your interests are but it's just something to consider. If you are interested in IM, FM and other specialties that aren't as competitive it is probably a non issue. Also of note is AZCOM's matchlist this year. While I don't advocate to choose a school based on a matchlist at all, I mention it as proof that some of their grads got some great residencies.
Regarding the weather here during the winter, this year it was mild and it really wasn't that bad. It's just like AZ in the summer but reversed. That said I prefer having seasons and ya it definitely took some getting use to not having sun 340 days a year but there aren't many places besides AZ and CA that you can have that.
Overall I think the clinical education is better at CCOM however our first two years have some amazing departments and some not so great departments. Our anatomy department is awesome, so is micro, physio and pathology. Our biochem department is severely lacking and in the process of revamping their curriculum, but that's the case for many DO schools.
If you have family that is within driving distance of one of the schools I think this is huge and can be a great support to you. Personally I've made close friends here and I love my class, I'm also an independent person so the distance from my family hasn't been that much of a factor but I think this is something you should consider above rotations and the other aspects. AZCOM and CCOM are both great schools and I don't think you can go wrong either way. Just go with whichever one you feel most comfortable with. Hope this helps.
The argument of there being too many students and not enough learning opportunities on the rotations in chicago is bogus. Each rotation has a limit on the number of students that can be there (from any school) to prevent such a thing. The difference is that Chicago has many more teaching hospitals (hospitals with residency programs) than phoenix does. This can be a good or bad thing depending on if the residents are good and help to teach you things that the attendings wouldn't otherwise have time to or if it detracts in that they do everything and you never get experience. To decide between this your best resource will be your classmates the year ahead of you and just see what they say about the individual rotations.
Here is a link to another thread where I answered some other specifics on CCOM.
http://forums.studentdoctor.net/showthread.php?p=8938976#post8938976
And here is a breakdown of what our fall schedule was like.
http://forums.studentdoctor.net/showthread.php?p=8993712#post8993712