I don't have SCTM, EMFOUR, WEEDM and I only have 1 PALMM. I'm not even going to guess how long the SCTM take to earn ROI. Really the only two miners that are probably actually worth buying are NeoXAgM and STEMM because the miners themselves should increase in value at a rate that's more profiable then any returns you'll get from mining.

I have good early results on IVM, which will decrease moving forward and ZZANM but I really don't own enough for acurate numbers.