I bought the vapor shark SwitchBox RX version of this mod. It works fine in wattage mod, how ever in temp control stainless steel it has a very noticeable pulse. I contacted vapor shark they refused to return the mod. Vapor shark exchanged the mod, I am having the same experience with the new switchbox rx.
Overall this device seems to work quite well. I have only used it in Wattage and TC SS modes, but both work well and the vape feels like it is hitting the appropriate temp/watts. Seems to be a little more stable, battery capacity wise, than the DNA 75 version. However, be advised that unlike most other VS products this does not come with the rubberized coating and the micro USB only provides 0.84A charging capability.