I've never had a smok tank that didn't leak like a running water faucet when using the RBA decks. I've tried different coils, different wicking methods, etc..... Still the same result unless I packed them so full of cotton they couldn't wick at all and it was nothing but dry hits.
I bought an OBS Engine a few months ago and it's the best tank I've ever owned. I really need to get 2 or 3 more.
I love the Engines. However, I was surprised to find the Smok factory coils for the BB/BBB way better than I expected for flavor. No leaks and excellent longevity. Good cloud as expected, but I'm more a flavor vaper. I haven't tried the RBA yet, so no idea what happens with that deal. But the Smok coils were decent enough for me to buy extras. As I primarily build, most of my factory coil tanks get chucked in the back of the drawer. These actually see use.