I have seen mixed reviews on the SI......Some say the 98 series may be as good or better, and others say the SI on the Onix is better.....especially farther out to the side.
Maybe Deil11 or Kosmo will chime in on this.
I would wait and see some more reviews of the new software update for the Onix.....If the reviews are good, I would give my vote for the Onix. Way better DI, and better 2D than the 98 series with the latest software.....You might even decide you like DI.
The Onix has MANY advantages over the 98 series if they get the bugs out of it......Sounds like the slow boot time may still be an issue if that is important to you.