I've brewed with both a banjo-style burner and a jet-style burner. I think the jet is louder, but the advantage is that it is more efficient. At least it throws off less heat outside your kettle. To illustrate this point, a buddy and I used to brew with keggles and a banjo-style burner. Because the keggle lacks a flat bottom, we used a grill grate from his charcoal grill to add stability. The best part about brewing at his house was that we could grill dogs and brats on the grate during the boil. The burner was throwing this much heat around the 17" keggle. When I finally bought a place with a yard, I adopted the same setup with a keggle and a burner that was unstable with a keggle absent a bbq grate. However, that burner I got was an SP10 with a jet-style burner. I don't bother to bbq on that grate during the boil because there frankly isn't enough wasted heat to cook brats very well. Maybe my burner is throwing off less BTU's, but since we always turn down the heat during the boil (boiling wort hotter doesn't raise the temp or make 60 mins any faster, so why waste gas), I think that the jet is anecdotally more efficient at boiling wort without a shroud or wasting heat.
