With catch can debate I thought I would do some research.
First - I don't sell them, and I'm not associate to any business.
Second - This not about whether you need one, as everyone is going to have their own opinion, but for those that are going to buy one, it may help you in deciding.
Manufacturers strive to separate the most oil they can, Toyota says it right in their patent. This video is more about what makes a good catch can so you can look at the inside and tell if you are getting a good one. Its actually quite simple, and in a nutshell the longer the air-path the better.
I'm not associated to Elite in away, but their design does follow the basic principles of good design better than other catch cans I have researched.