If you had your choice, what would you build up.
I first would check to see what one fit me better. Then, I would notice that I fit a bit better on the Planet X and pick that…oh wait - I did.
geometry first as was mentioned. After that, looks, color, local bike shop support, etc. Both fine machines that won’t likely be your limiting factor 
Did this. Just trying to make a decision. I am partial to the Specialized, because I had a 07 Comp at one point and it was nice. Upgraded to a more expensive carbon bike that I no longer like.
PX is a 76deg bike. For me, that would be the decision maker right there. Based on it’s seatpost, I couldn’t ride the bike.