Back when i started I looked at both those guys heavily. I ended up buying the mile hi 4" 4 plate column setup but got the boiler controller and some supplies from hillbilly. In the end the all copper setup lost out to the modular mile hi.
That all said, had still dragon been going at that point it would have been different. Now, still dragon seems to offer almost everything a fella could want.
Two exceptions. First mile hi perf plates for the 4" are superior TO SD perf plates and easily keep up with flow rates on the pro cap SD for vodka purposes.
Second, when it came time for a larger boiler, I sourced a custom design from china directly for a fraction of the cost of anything from SD or the others.