Having been at CMU for several months now, I've formed a few opinions regarding the school, especially in how it contrasts to Cornell, where I spent the previous five years.
First of all, I must say that it has been a pleasure working and interacting with Carlos and his group. The group's research profile covers an impressive breadth of interesting research topics, ranging from large-scale machine learning, efficient non-parametric inference methods, probabilistic permutation models, and novel ways of managing our growing information overload.
From a grad student's perspective, the thing that stands out most is the fact that students must choose advisors within the first month of starting. In contrast, at Cornell, students typically settle on advisors sometime during their second year, and are encouraged to spend their first year taking project courses and "shopping around". Both styles have their benefits and drawbacks. Students tend to start working on serious research projects much sooner at CMU. However, those who wish to spend some time exploring different research areas will likely feel much more comfortable at Cornell.
As a school, the research culture at CMU is significantly more focused on computer science than Cornell is. Oftentimes, one gets the impression that the entire school revolves around computer science and related fields. In contrast, research at Cornell is much more diverse, and this is reflected in the graduate student culture. On the other hand, the relative proximity of different research areas at CMU seems to foster more collaboration between research groups.
As a city, Pittsburgh has been more agreeable to me than I was expecting. Located on rolling hills and at the intersection of three rivers, the surrounding landscape can be quite beautiful. I recently learned that Pittsburgh has 446 bridges! (Although it's unclear how bridges are defined in that statistic.) The city is also entrenched in culture from its steel boom days, although I haven't had too much time to explore that aspect thus far. I particularly liked the Google Pittsburgh office, which had the feel of a converted steel mill.
And the CMU campus isn't half-bad either:
All in all, it's been an enjoyable experience thus far.