Quick and dirty answers, directly to the questions.
Q: Will rsync make the comparison when copying the files between two local drives? A: It will do comparison to figure out what to copy.
Q: If it does do a verification - is it a safe bet? Or is it better to do a byte by byte comparison? A: as safe as the mathematics behind MD5 checksum of file. You can try to do simple experiment to learn and trust the tool.
Long answer: I guess, you wanted rsync to do file comparison (bit by bit or by checksum) after copying files. If you are one of the few that value data integrity, you might find the below useful:
rsync -avh [source] [destination] && rsync -avhc [source] [destination] #above code rsync files folder on first run and if complete without issue, will run rsync again immediately while performing same file name comparison by using hash of entire file.
