Amazon:
I have attended the new grad SDE interview. Typical new grad interview process like the https://leetcode.com/discuss/interview-experience/908779/Amazon-or-SDE-New-Grad-2021-or-Seattle-or-Oct-2020-Offer.

Based on my experience, one who practiced Amazon tagged questions should able to perform very well. Their questions are straight forward, like traverse a tree zig-zag, mirror of a tree, do DFS/BFS on a 2D matrix to find disconnected components, LRU cache...

Interviewers had a serious face for the entire time of the interview like they were having a rough day. The last interviewer was like 10 minutes late. Out of 3 Virtual rounds none of them had simile on their faces.

One of the interviewers asked me to Give a time when you went above and beyond the requirements for a project.
I started saying, I built an Android app... The interviewer interrupted me and said say something from your CO-OP. He was not even interested to know about apps I built just for fun.

Overall it seems the entire interview process was mechanical.

Microsoft:

This time I was interacting with happy faces the entire time. But the questions were so hard. I never seen these questions before

The recruiter reached me out on the phone, and I had to complete OA. OA consists of CS basic questions like B+ trees, time complexity, bug fixing, and writing code for 2 problems.

I lost hope after writing the test, but the recruiter told me I passed the test and scheduled 4 Virtual team interviews.
3 rounds are related to coding, all of the questions are related to Dynamic programming. One interviewer said, hint: this can't be done in less than O(n*n) in 45 minutes.

Just doing frequently tagged Leetcode questions doesn't work for Microsoft. However, I enjoyed the interview process, interviewers really helped me to solve the problems, they mentioned some edge cases and I fixed them.

The last round was with the hiring manager, we both had a great discussion about apps I built and the culture at Microsoft. I tried to highlight apps I built, a kind of nudged my behavioural answers around them.

I got offers from both Amazon and Microsoft. Both offered me around 160K USD.

I am choosing Microsoft.