Still ugly! 
thanks for your criticism,that's just prototype one, batch production will be much more beautiful.
If they are strong enough to stack on each other, you are fine.
I was just looking at the new units posted on the Rockminer website and I actually think they look pretty good considering what they are and what they do. My only concern was the fashion one side of the boards are secured to the case...seems like a weak link and I'd imagine there will be issues during shipment causing bent/broken. I would recommend changing the boards to a vertical position to relieve stress on the boards as well.
If you look at the upper board you can see the deflection from the weight of the heatsinks.
I think the first board's heatsink is 2 pieces that's why the PCB looks bend. Other 3 boards are fine. Keeping it vertical will ask for more metal and may be not very steady if not.
However I have a feeling that original Fridcat or s1/s3 design is superior because of the formfactor. The current rockminer design (though ultra simple) takes a lot of space in a shelf.