I think Tsubasacon had the date first, then Sugoi 
swiped it for themselves (maybe to try hurting 
Tsubasacon attendance) - Sugoi has done that 
practice one other time taking another smaller 
regional con's date and announcing it as their 
own.  Not very nice thing to do, I could see it 
possibly happening once by coincidence but not 
twice.

I have tried Sugoi a couple of times, but never 
enjoyed myself.  I may give Tsubasacon a try to 
see if they have better events.