I have owned all 3, the M5G is the best one, unless you throw in the SL-1200GLD which I also own. The M5G has a titanium tonearm and a black metal flake paint job. It has the pitch control numbers illuminated, the pitch control is digital and does 8% and 16%. It also has the better tone arm wires. It also has a pitch reset button that locks the pitch at 33.3 or 45. The MK5 has the rest button also but the pitch only goes to 8% and is not digital. The mk2 doesn't have the reset button. They all have a LED for the popup light except for the MK2 which has a regular bulb that sooner or later will burn out. Technically the M5G is supposed to sound better than the others, but I can't hear any difference, it might be just my hearing, or my system, or the fact that I have no way to switch them fast enough to do a comparison. The 1210 is a black version of the MK2, but not all of them have the 220v switch.