[vtirocz]

I'd check both colors out in person if you can. I think the pictures don't always represent these two very well.

Riverside is a nice color, but does have a bit of a purple hue to it that doesn't always show up in pictures. CW3SF's pictures actually seem to capture the color really well. When I first saw pictures of Riverside, it looked almost exactly the same as Hyper Blue, but in reality the colors are much different.

Similarly, Shadow Gray has a "blue/green" hue as captured in some of the pictures above.

Can't go wrong either way!