Heroku Comparator App
There is a very good Heroku app for the same: https://perm-comparator.herokuapp.com/
PROS: Very easy to compare multiple profiles and produce a comparison table.
CONS: Runs on Heroku server – Security concern. Also, do not give next level drill down like FLS check, apex classes
AppExchange Packages
Bulk Object Field Creator: https://appexchange.salesforce.com/appxListingDetail?listingId=a0N30000000qDqqEAE
Profile and Permission Set Helper: https://appexchange.salesforce.com/appxListingDetail?listingId=a0N3A00000FeF99UAF
Arxxus Profile Comparator: https://full5-sites.cs69.force.com/appexchange/appxListingDetail?listingId=a0N3000000DY0WgEAL
PROS: Native app in Salesforce. Easy for system admin.
CONS: Do not produce as good chart as heroku app.
GitHub
Being a developer I like this as it gives you full control. But you need git + Workbench expertise
You can have two branch with a file having all metadata of a profile (which can be easily pulled by using workbench). After that pull a request, it would show all differences as conflict.