I consider that an epic fail. The last thing I want is to confuse the two, or to have to laboriously manually separate tabs into windows. That's not to mention that I also don't want to share the passwords between the two profiles either.

What's the most frustrating is Firefox already has multiple profile support. All it's missing is an ergonomic way to switch and manage the profiles.

You can have two desktop shortcuts with different icons that start the browser with different profiles. With different profiles you can make the browser windows have very different customized looks and differnt profiles also have separate password storages.