Quite casual, just two interviewers, (30-40 minutes) mostly asking about my degree and understanding of the job. Before and after this I took the tests on problem solving and arithmetics which were of varying difficulty and to be down under a short time constraint. I didn't finish all the tests (20-25 questions in each) in the time given (30 minutes each) because they used negative marking for incorrect answers. Was there for about 4 hours maximum after getting all my documents scanned and got the offer the day after.

Relatively straightforward interview; 4 GMAT tests (shouldn't be too difficult with some practice online) and then a pretty standard interview asking about you as a person. They generally give you the offer based on your GMAT score so practice is essential. Quite a laid back and easy going environment so no need to be nervous :)