My experience has shown two distinct behaviors.
Case 1: Placeholder Profile "Profile 27" created in production. Production org copied to Sandbox. Development and config occurs in sandbox. Change set is used to promote code, config, Profile 27, as well as field-level and object-level security. This works.
Production org copied to Sandbox. Development and config occurs in sandbox. Profile 28 is created in sandbox. Change set is used to promote code, config, Profile 28, as well as field-level and object-level security.
After deployment Profile 28 exists in Production, but the FLS is foobar and must be configured by hand.
It appears that in order for object and field level security details to promote correctly with a profile, the following must be true: 1) profile is included in change set 2) objects/fields to which profile has access are included in change set 3) profile must already exist in target org, and must have been populated to source org by copy/refresh
Is there any way of creating a new profile in a sandbox, and promoting it to the production org in such a way that Field level and Object level security is correctly promoted as well?