Other than the obvious (the shape) what's the difference between Vance & Hines Twin slash rounds and Ovals? Does one sound better than the other?

 

Assuming you are talking about the Twin Slash Ovals, and not the monster ovals.
The ovals offer a slightly larger internal volume, which gives a correspondingly deeper tone than the rounds. Mine actually sound closer to the High Output 4.5's.

Plus I like the look better.

 

I'm sorry, yes I mean the Twin Slash Ovals. I had these on my old 2005 RK and liked them. I wasn't sure if there was a difference in sound between the two. I guess I'll stick with the Twin Slash Ovals since I liked them on my old bike.