Been using mine for a couple days, definitely enjoying it. The smaller size deck style of this and the Billow 2 can be a PITA to work on, have had more than my fair share of rage inducing, coil warping, leg snapping shorts, but once built up properly it's been great. Flavor is very good, airflow options are very good though it can be tricky to adjust on some (most) mods without a paperclip or something, capacity is better than expected for the size, as far as that goes looks are deceiving(this thing is truly MINI), it's much smaller in person than it looks in pictures but holds a fair amount of juice. You really cant beat 3 mL for a tank this size.
I'm using 28 and 30 gauge kanthal twisted together, flavor is fantastic and about the same between single and dual coil, the flavor is a hair fuller and more 'moist' with duals, though juice consumption is drastically increased, so I'll probably mostly be using it in single coil mode. Now that I really think about it, its hard to say which mode has better flavor, as the single coil plug also inadvertently acts as a chamber reducer. I'll have to go through a few more tanks with different juices to reach a final verdict on single vs dual flavor, but either way in either mode flavor is above average to excellent and holds it own against my other flavor RTA's and even drippers.
Aesthetically, the piece itself looks VERY nice, but out of place on some mods. It looked plain stupid on my IPV Mini II IMO(that could be due to the wrap on it though, its a 'busy' design, but oddly enough I think it just might work looks wise on the IPV 3, but that's reserved for drippers and bigger tanks). However, it looks right at home on my black Evic VT, and that combo is an oddly pleasing compact set up. A nickle build is therefore inevitable

. Also looked pretty nice on my Skeleton Key, though too bottom heavy in 18650 mode to convince me to want to switch out the Lemo Drop I usually run on it (mainly for the 23mm size) Would probably look amazing with an 18500, but that's the nature of that particular mech anyway. (which reminds me, I have actually never used any other batteries besides 18 and 26 650s, I rotate 10 Samsungs, 2 MNKEs, and 4 Sonys, but have never owned or fired anything else, anyone care to point me towards a write up/thread on the smaller batteries' safety and the types of builds appropriate for them? I can figure out the amp draw and everything and find a range that would be safe if I do go ahead and try them out, but seeing real world examples is always better than just doing the math for me. Thanks!)
Leakage has been surprisingly non existent. When I first got the tank apart to check out the deck and saw straight through the airflow I thought for sure it was going to be a major major issue. However, it hasn't been at all, and I wicked slightly heavy on single coil build 1 and slightly light on dual coil build 2 with no particular attention given to getting the wick perfect to sort of test out leak potential. Nothing more than the usual condensation, much less than what would be in the base of an OG Lemo when going for a refill. Lack of leakage could be due to a sort of muscle memory from wicking the similar Billow 2 this past month, YMMV. The Lemo, that brings me to the biggest con I have so far, the bottom fill and the way it's implemented. Bottom fill I can deal with, and flat head screws I can deal with, but flat head bottom fill screw? Hell. No. I suppose it looks great, nice and flush, absolute nightmare to use. Quarter turn-driver slips-quarter turn-driver slips-quarter turn-driver slips annnd the screwdriver is tossed at the wall. Filling as a whole could have been implemented much better on this tank, either by a chimney with 2 separate thread sections ala EVERY OTHER RTA I use for an easier time at 'unoffical' top fill, a dedicated top fill like Youde apparently was claiming, or something similar to the Lemo's silicon plug. Anything really, with the different colored glass sections available it seems Youde is going for customization on this tank, I'm just really hoping spare parts etc become available, specifically Philips fill screws or a silicon plug. That single coil plug and the fill screw for that matter will inevitably find their way into the depths of the post screw and o ring black hole, so I hope that piece will eventually be available as a separate purchase as well for those that do end up losing it. They did GREAT with that deck plug, so I know they have it in them to come out with something better for the fill port. Most likely wishful thinking, as all that is A LOT of support to ask of a $30 Chinese tank. While I'm fantasizing on extra parts, a chimney that isn't one big female thread would be nice as well, and hell let's throw a reverse drop kit on that list as well. Could look really nice, a 5 or 6 mL tank with minimal steel, though it would become somewhat of an at home show piece for likelihood of breakage at that point.
All in all, I do highly enjoy this tank and am overall very happy with my purchase. I would not recommend it as someone's first RTA, but for those who have some experience with rebuildable tanks you really cant go wrong if you have a mod it will match up nicely with. Flavor, vapor production, airflow and looks are all top notch. Single coil mode on a 4 post tank is a fantastic option to have for those of us who prefer single coils and I suspect will make nickle builds much easier than perfecting a dual nickle setup. Filling can definitely be improved and the airflow adjustment is neither bad nor exceptional. It gets points for the unique design but can be a bit of a pain to adjust without a tool or long fingernails. I definitely recommend this tank to RTA users, it wouldn't be great as someone's only RTA but makes a very worthy addition to a lineup of tanks. All in all, it has its place amongst RTA's, and it fills its spot well.