Ox vs shapeoko 3 half plywood

So I pre ordered the shapeoko 3. I will be building RC plane parts from wood and balsa. So I know shape 3 is small but upgrades for bigger are promised. But the more I look at the ox the more I relize the price will be better in long run. How sturdy is the ox. What accuracy are people seeing. And how do u think it compares to shape 3. Thanks

 

So is accuracy the same

 

Also I want a bigger machine. And the shapeoko will cost more because I need upgrafe rails

 

I can't decide. The ox looks beefier and I can make it bigger. But shapeoko looks nice still. What's better on z acme or belt