Personally, I liked Case much more than CCF. I felt that the residents at Case were friendlier, more personable, and seemed happier than those at CCF. I also got a weird vibe on the interview day at CCF, and was told by one of the residents that the ORs were intentionally built far enough away from the ER so that CCF couldn't be a level 1 trauma center, because trauma patients lose you money. This was a turn-off to me personally, as I want to work in underserved medicine. As far as training goes, I'm sure you'd be well trained at either one. I like having a VA for more bread & butter IM cases, so I felt Case had a slight advantage.
Fellowship placement at both is great, with solid match lists for the past few years. I was a little bit more impressed with Case's match list, but they were comparable.
All this to say, you'd do well with either place. Although I liked Case better, I'm sure there are those that liked CCF better, and arguments can be made for either one depending on your career interests.