I'd worry that if I hadn't bothered to calibrate my monitor or had done it incorrectly, PhotoShop would be embedding bogus information which might be wrongly interpreted by a print bureau, say. I prefer the KISS approach - Keep It Simple, Stupid!

To check that the images were identical, I compared them in Paint Shop Pro, which definitely doesn't support monitor calibration. I then viewed the files in Wordpad to see their general layout and read any embedded text. With experience it's possible to pick out header information (not necessarily at the beginning of the file) from image / preview data and to spot if compression has been used. Finally, I used MS Debug (a simple hex editor dating from the early days of DOS ) to obtain the precise information.

Regards - Sean