Yep.
No Game No Life is a popular anime, so the possibility that more manufacturers [GSC, Alter, etc.] will release sculpts of her during this upcoming hobby event is decent, and Kotobukiya prices generally fall after release and/or are usually easy to find on third-party sites for/around MSRP, oftentimes cheaper.
The Skytube/Tony Taka stuff, on the other hand...good luck. I mean, some you might be able to find for at MSRP [if you're lucky], but they have a tendency to increase in-price pretty rapidly, just look at the first two Fault! figures released by them.
Basically, I like both [and haven't said a permanent "no" to Shiro], but if I'm going to pre-order one of them, it will be Sugie San. Shiro I'll try to find for a bargain post-release, assuming GSC/Alter/etc. don't release one that looks even better.