I think the "advantages" of completeing some specialty (usually general surgery) prior to starting training are a few.
1. you're already pretty technically polished @ this point & you more into small refinements then having to learn how to be a surgeon when you do larger cases. This is a big advantage during a very technical specialty training.
2. reconstructive surgery is very much similar to my experience from hundreds and hundreds of trauma, vascular, and various general surgery cases. The transition for these is pretty easy & the perspective with your prior training is invaluable. Also important is the level of discussion that you can have with referring surgeons b/c of common experiences
3. There is a clear difference in your maturity level when you're doing something at the level of a fellow. This is important on so many levels in the way you make decisions and analyze things as well as handling real problems
4. You're pretty much able to handle just about any scenario with patient care, which may or may not be true of the integrated programs
As far as marketability, I don't think there's really much of an advantage to being double boarded these days talking to most of the guys I work with. Most of them would say that patients rarely ever ask their credentials. Some relative disadvatages to doing surgery prior include:
-some experience which clearly will not benefit you much (endoscopy, advanced laparoscopy, some ICU procedures), but these are just a fraction of your time over 5 years
-it can add some length to your training, but usually we're only talking a year here. BTW, many programs have actually DROPPED mandatory research years rather then added due to funding issues. It used to be much more common then now. At many programs its completely optional these days
-you will not be able to train at some programs with integrated only spots
-its physically harder
People who say "I want to do Plastics, but I could never do Surgery" make my eyes roll. This perspective usually makes for pretty mediocre surgeons to me and is pretty short sighted about how similar large parts of the fields are. If your goal is to do exclusively facial aesthetics then you're clearly not better off considering general surgery (or even PRS for that matter) & facial plastics after ENT might be the best route.
The main problem I think the integrated experience has is that you end up trying walk & run at the same time, learning both technique and information. The important parts of surgical training are just hard to compact & the what you end up sacrificing are the experience that's most valuable. Programs where all this synergizes & works well are pretty few I imagine
