Welcome to the world of cnc'ing! You are going to love your new toy.
I'm with you 4D, what is that little triangle cutout for? If it is not for mounting something then it looks like a finger trapping problem. I would not think it would be for weight reduction.Looking great! First photos I've seen of their new design. Very curious why they have the open triangle on the gantry risers.
Looks like they've also upgraded the steppers they are using. Thanks for posting those photos.