The moon buster wins
Would actually be willing to say Yamamoto would win here. Roshi's strongest Kamehameha attacks require quite a bit of prep time and I highly doubt he can pull one off against Yamamoto in this match. While both are about on par in speed, Yamamoto's ability to fly will give him a major advantage here as he could avoid the majority of Roshi's attacks and attack him from a distance using attacks from his zankupatou. Roshi's at too much of a disadvantage here.
@taichokage: Roshi is a master martial artist and has ki, i am sure he can sense it even if it is invisible, and it is undoubtedly that Roshi is indeed faster than Yamamoto..
Also, it's impossible to be 15m C, if such a thing existed on the planet, the world would be destroyed in minutes. He also stated that it wasn't 15m C ( i read it in another debate i forgot what, i think it was your debate against yusuke52? )
It's 15,000,000 C. 27,000,000 F.
Only thing I agree with from eddz99 is that the claims of the temperature for Yamamoto's fire attacks sound like hyperbole considering such temps could vaporize an entire planet instantly if Yamamoto were indeed capable of using them. But otherwise, the temperatures emitted from the sword should still be enough to cause Roshi to get incinerated instantly.
Roshi is indeed faster than Yamamoto..
Roshi at his strongest is only capable of Mach 10+ movement meaning Yamamoto shouldn't have any problem keeping up with him. Characters in DB are nowhere as ridiculously fast as they would be in DBZ (fastest being about Mach 30 by stronger characters like Goku and Piccolo), especially when Roshi becomes ridiculously dwarfed by all the fighters he had trained. Not to mention Roshi lacks the ability to fly which Yamamoto could milk enough to spam attacks at Roshi from a distance.