I got my iStick 50 on Monday and haven't put it down (and haven't had to recharge it yet!!!!!) Running Kanger SubTank Nanos (0.5 and 1.2ohms) on it. Very delightful
I don't believe it can go below 0.4 ohms. Other than that, no reason not to drip on it. It's basically another mod with a really long-lived battery
ETA: I lied. Specs indicate it can go down to 0.2 ohms