I prefer the bushing barrels, I want the gun as light as I can get it.
With that said there is a case for a bushing barrel. If you are going to go full tilt with slide lightening the bull barrel will allow you to take another ounce or a little more out of the slide while maintaining a sane slide velocity. I have a bull barrel in my STI 40 for this reason, otherwise it would have a bushing barrel in it.
If you aren't going to lighten the slide stick with a bushing barrel, especially with a steel framed Para. Those things are about the same weight as an armored car anyway......
Not picking on your gun, I really like the Para guns but prefer my racing guns much lighter.