GUID vs INT IDENTITY [duplicate]

Kimberley Tripp (SQLSkills.com) has an article on using GUID's as primary keys. She advices against it because of the unnecessary overhead.

To answer your question:In the end, in what circumstances would you see yourself using an INT as a PK versus a GUID?

I would use a GUID if my system would have an online/offline version that inside the offline version you can save data and that data is transferred back to the server one day during a synch. That way, you are sure that you won't have the same key twice inside your database.

We have Guids in our very complex enterprise software everywhere. Works smoothly.

I believe Guids are semantically more suitable to serve as identifiers. There is also no point in unnecessarily worrying about performance until you are faced with that problem. Beware premature optimization.

There is also an advantage with database migration of any sort. With Guids you will have no collisions. If you attempt to merge several DBs where ints are used for identity, you will have to replace their values. If these old values were used in urls, they will now be different following SEO hit.