Which should I choose, CSAM at IIIT Delhi or IT at IIIT Allahabad?

Since you know what you are looking for, it becomes quite easy to segregate categories for you to choose which place you want to go. Do all-around research and look at various categories like crowd, course curriculum as well as the faculty before making a decision. Here are some points that may help you out.

Faculty: One point where IIIT A might lag is the faculty. Being a top college, you might expect it to have some of the top-notch faculty in the country. However, it is more of a mix of government college faculty with some average teachers and others that are really well-versed in their subjects. IIIT D on the other hand has better faculty who have a rational approach to the subject of computer science. IIIT D definitely tops here.

Course Curriculum: You will find some of the best course curricula at IIIT A. You will be introduced to the subjects of computer science right from the very first semester. A major plus point is that there are no interdisciplinary subjects like ED that will be included.

Crowd: As far as crowds are concerned, both places have the same crowd. IIIT A might be slightly better as they do not hold any state-based preferences or quotas.

Coding Culture: The coding culture at IIIT A is one of the best in the country. This college is the pioneer college that represents our country in some of the most major competitive coding platforms. Just recently, 12 students were even selected for GSOC from IIIT A. IIIT D is still in its nascent days as far as coding is concerned.

Infrastructure: This is one point where both colleges are at par with each other. Both are good as far as basic amenities are concerned.

Lastly, you should know that IIIT A is a college with a national reputation. It will definitely give you the upper edge when you go for your masters. This is probably not the case with IIIT D. However, if you are looking for good faculty and a city atmosphere, go to IIIT D.