I've had a Cubis Pro for 2 weeks now, works great w/std Notch coil, but there's a LONG story to it.
I examined and studied it closely before putting it to use.
The redesign top-fill does NOTHING to fix the flood-on-refill issue. If anything, it makes it more prone to flooding, and makes it harder to prevent by DIY methods.
Pros: more airflow, 0.5 ml more juice (insignificant IMO)
Cons: still floods-on-refill, smaller fill area - harder to refill, more complicated - 2x the o-rings, harder to clean.
Background - I had been using a std. Notch coil (5-pack) in my Cubis/Cuboid for a week (was working great at 45w/400ºF) when the Cubis Pro arrived (got it and an iStick Pico together).
The Cubis Pro came with 4 coils: 0.5 SS, 0.25 Notch, QCS Notch and LVC Clapton. I chose to start with the QCS Notch, and compare to the Cubis/Notch as reference.
The QCS coil is very easy to prime: take bottom cap off exposing the wick, drip juice until wick is saturated, put cap back on!
Installed on the Pico at same 45w/400º, coil registered at 0.27 ohms and locked in.
Took a hit and blah, nothing, barely a wisp of vapor. Letting it sit and soak did nothing to improve it. Cranking the wattage & temperature up helped some, but still poor unsatisfying vapor.
So on a lark I used the TCR settings. It got better at higher TCR values, finally settled in good at 150 TCR! Reduced the wattage & temp back down to 45/400º, and it was almost identical to the Cubis/Notch. Lots of vapor, great taste, very satisfying hit!
But it was notably different: it NEVER spit or crackled! just gave an uniform sizzling sound.
At this point I presumed that the QCS was a completely different creature than the std. Notch coil, but I was very happy so continued with it.
But then another issue crept in: every hour or two it would begin to make a "slurping" sound, and vapor production would drop off. Flooding I thought? But no, on the QCS coil you can see right down the chimney to the gold-plated bottom contact plate - there was NO free liquid inside the coil!
Flinging it with a tissue wrapped around the top would produce big wet patches, but it was NOT coming out the drip-tip, it was coming out the AIR VENTS! It would vape good again for another hour or two, then repeat.
I suspected condensation, so when the tank got low and began slurping again, I took it apart. Sure enough, the recess in the top of the coil was full of liquid, in the path of intake air, while the bottom of the coil was dry.
The std Notch coil has a screen on top, so any excess liquid can flow back through it into the wick, but the QCS coil has a solid metal ring, so liquid CANNOT flow back into the wick.
And since the condensation liquid forms around the periphery of the metal ring, when you fling it, it goes up the outer airflow chimney! Poor coil design.
I get the feeling Joyetech is just "flinging" ideas against a wall to see what sticks, then going right to production without any testing, and we're the guinea pigs.
I was fairly disappointed, but since it was working good in-between "flings", I continued with it ... until day 5 (good news - it NEVER flooded just from sitting over night).
On morning of the 5th day, my usual routine, got a cup of coffee, sat down at the computer, took a big hit - very good, got my nic fix in. Over the next 10-15 minutes got 3-4 more good hits, then BOOM, MASSIVE burnt taste!
Letting it sit for a while, and even loosening the top to "promote" flow into the coil, further hits still had the burnt taste.
Disgusted at this point, I pulled it out and replaced it with the std. Notch coil that came bundled with the Cubis Pro.
I set the Pico back to the default SS316 mode at 45w/400º, and it was PERFECT! Just like the notch coil in the Cubis. Go figure. I'm presuming (but don't know) the QCS coil has a different metallurgy coil, or is just a bad design.
Something to note: the Notch coil that came w/the Cubis Pro has a MUCH finer spit screen than the Notch coils in the 5-pack I bought. An improvement, but Joyetech must still be "experimenting".
7 days now, and while it makes the spit crack sound first few hits in the morning, it has NEVER actually spit anything out into my mouth!
7 refills now, and NEVER flooded - because I've devised my own rube-goldberg "cure": plug the drip-tip & airflow holes while filling, then quickly remove the plugs & screw on the cap.