I would say Memory or Mother for iDev, since Memory pretty much is Nessa but better, and Mother was one of the best sparring guilds after US stopped doing many of the GSTs. Also, don't forget that last GST, not many people really thought Nessa would get to the finals or even the semi-finals, but they managed to take first place in the iDev tournament, which means that any underdog has a chance at ranking high. As for mixed, I would say Alumni.

iDev
Possible winners: Alumni, Memory, Blitz, Apostles or 5pa4.
Dark Horse: Raindrop

Mixed
Possible winners: Alumni, SLX, Memory or Apostles.
Dark Horse: the R0ller

Hazard will make finals so I get Kosmas 1k farm

those noobs suck

Here's a bug. Halfway through spar everyone just disappeared and I was standing alone in the arena on my screen. As soon as we won and the spar ended I could see everyone again. Saw a few others complaining about this as well in spars I watched. So that's weird.