I have two folders, and like you pursuing ground clearance bought both of those derailleurs. They're both good. As Maddog says, the Microshift requires a Microshift shifter - Acolyte & Advent (which I got) both work.

I measure ground clearance at 75 mm for the MS (which you can see on my bike here), 60 mm for the Altus. Tensioning capacity (wrap) greater for the Altus: 43t vs 27t listed for MS (but it will actually wrap more, as I learned from John Flores: 35t with chain running clear, 39t in a 2x setup if you allow contact - which clatters but isn't dangerous - in the two highest gears in low range - which are redundant anyway).

Grant Peterson of Rivendell calls the 310 "the best-designed cheap rear derailer in existence" - you can read his take here.