Been to yokohama arena before for some concerts (Nana Mizuki) several years back. It is BIG. But if compare to Makuhari messe though...well it depends how many halls of Makuhari Messe we're talking about here (since Makuhari is basically an Expo/convention centre)
But do remember again that it's indoor, so the place might be abit cramped if its divided into several stages...
i think someone posted their @ jam expo experience in this forum before. Like, the place abit hot inside and "sound bleeding" from the next stage etc etc. but then again nothing is perfect, i also got some problems with TIF as well (like how far the walking distance between one stage to another, etc)
But the main advantage of course it that it's in indoor venue eh...can just avoid the sun, and probably no need to walk so far in between stages lol
For me i still prefer TIF though!