"I've never smoked a metal pipe. Describe the benefits."
Well, before anything else be said, keep in mind that not all metals smoke the same. Having said that, certain generalizations can be made. Metals were designed primarily to provide a very cool, dry smoke by effecting condensation of moisture in the smoke and by trapping much of the goo. All of the metals I currently have (there are more on the way) do quite a good job, although some are better at it than others.
In addition, metal pipes are extremely sturdy and can tolerate mishandling much better than briars,not to mention meers. Furthermore, they are quite easy to clean and maintain. Finally, they are certainly unusual compared to most briars and always attract attention.
The major downside of metal pipes is that they (with the exception of the Falcon models) are no longer in production and are thus not readily available. So, metal devotees like myself depend on sites like Ebay and Etsy, and on forum posters who are willing to trade or sell.