The 24x24 dimensions are roughly what you'd be looking at either way for a cube .. though maybe not as tall as 2 feet to lower the gallons, so all-in-all, I think the Deep Blue is best bang for your buck, and a true cube, and RR.
I will say this though - their bulkheads are complete garbage. Throw them out. They did nothing but leak for us, and I know numerous people in the hobby who had leaks from their Deep Blue bulkheads. I recommend going with slip bulkheads of higher quality and using spaflex for tubing to your sump.
Also, just to let you know, if you were to get the 24x24 stand .. it is very tight to fit a sump. You can see how much bigger his stand is than the tank (Roughly 31x31 stand), and it barely housed a 20g high sump with a small 5g ato tank. He ended up drilling into the basement out of frustration of trying to work in the tight space.