The Core is fantastic. Think faster, flippier z-buzz.
The Riot is not so fantastic for me. Lots of early releases due to the beveled edge (anyone who disliked the QK for this reason, raise your hand
). Pretty decent speed but not blazing fast, decent glide, etc etc. Kinda similar to a Viking (but harder to throw decently), IMHO.
Got my first throws with it with mostly less than full power and into a headwind. One low throw with max. 80 % probably less power into a about 7 MPH headwind flipped quickly to flat and flew on a frozen rope to 270' without any fade whatsoever. Not an inch as far as I could see. On a previous round a gust hit the disc head on and it flipped 15-20 degrees instantaneously early in the flight when it was flying fast. So it's not a Predator in HSS nor LSS but still for mild winds or non gusting medium winds this is a fine disc. I'd say people with 330' or more power will have much better results with this disc as less powerful throwers. It seemed fairly easy to throw but I need more experience with it. It competes against SOLFs and may even win but the jury is still out.
QK2 of the pre run were much easier to slip out than the Riot but I did have one when I had a sloppy quick preparation for the throw trying to throw when the wind died down between gusts. Riot's rounded rim to wing connection definitely helps small hands to get a better and tighter grip being a little easier to slip early than many traditional discs. Not unmanageable as long as you remember to grip tightly enough with the index finger. Nowhere close to the horror that the QK2 pre run is.
To me it seemed that the HSS of the Riot was higher than the Viking should be. I haven't thrown a Viking but have Discmania CDs that are more HSS less LSS developments of the Viking. Without throwing side by side in decent conditions I can't be sure of CD vs Riot but they are roughly in the same category stability wise but the Riot is probably less LSS and faster and it feels easier to get farther even with less than full power.
Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.