How do you live in AK and rarely ride powder?!
But yeah, if you just like speed, stability, epic carves and more - go with the CX.
But honestly, there are A LOT better boards than the roundhouse for doing what you want to do. I see the roundhouse as more of a powder/backcountry type board (rx obviously)
The CX seems like it would just get boring after a while. Do you do any side hits, or jumps? Do you want something more playful you can mess around with more? Or do you strictly just carve up the mountain and spit it out?