If it is in fact between 16-25k then it couldn't possibly be more expensive than the YBR... which sounds nice.
If I may; a comparison between the GW250 and the YBR250:

GW250: 6 speed - 18.9KW - 23.8Nm torque - 26hp... that sounds nice too.
YBR250: 5 speed - 15.5KW - 20.7Nm torque - 21hp... =(

That's considerably more powerful than the YBR, although, there is one thing I noticed in the picture above: It says the bike is 182kg. The YBR is only supposed to be 138kg wet according to one of ZMC888's posts.

GW250: 182kg...
YBR250: 138kg... =)

If the YBR is in fact over 44kg lighter than the GW then it may make a difference if the two bikes were to have a little race.
My guess is that the GW250 will burn a larger amount of petrol with it's twin engine and extra weight. In that case, the YBR is the more fuel efficient option. Still, I like the sound of a twin.