如果我使用GUIDs作为主键，那么使用Rails 3.1是一个好主意吗?

I'm using Rails 3.1 with PostgreSQL 8.4. Let's assume I want/need to use GUID primary keys. One potential drawback is index fragmentation. In MS SQL, a recommended solution for that is to use special sequential GUIDs. One I'm using Rails 3.1 with PostgreSQL 8.4. Let's