Tomocon is trying really really hard to be a threat to Nishi though. I literally heard this story from a friend of a friend of Dian and Erik, but apparently Tomo picked the same date on purpose. Nishi had been advertising their event for months when Tomo suddenly announced their date. When Dian and Erik asked them why they didn't pick another date, Tomo claimed their venue was already booked for every other weekend that month.
Eventually Erik called Tomo's venue somewhere last year, pretending to be an interested client to check. The venue said they were totally free for every other date... Kinda a dick move if you ask me. Most vendors that were going to Nishi signed up for Tomo right away, because Tomo promises them many visitors.
Personally I think both Nishi and Tomo are shit, but I don't understand why the con world has to become so toxic. Again, not 100% sure if all of this is exactly true.