Ok here's a late review for the Russian 2 (clone).
I have been side by siding it with
1. Russian 91%, (real steel),
2. a K4, (real steel also),
3. a Russian 3 (clone),
Note: UCT should stand for not for noobs ???

The clone I got, (which has since "Temporarily sold out"), is a very good quality one,
and has not drifted far, if at all, from the real steel.

The machining compared to the R91 is spot on.
The materials, well I can't tell the difference between it & the R91.
I've had it running for four months now,
& I have not noticed the steel wearing, if at all.

The air flow is very similar to the K4, but vastly easier to adjust.
I find to assist the wicking, you need to run it tighter on a full tank,
& open it up as the level in the tank drops.
Also see: https://www.fasttech.com/reviews/2171901/405113
about the rubber layer under the air flow ring.

Filling, don't use a needle bottle, you will grow old waiting for it to fill.
Use one of those thinner nozzles on a juice bottle, (the fat ones don't fit).
Forget a glass dropper bottle, unless you want to try and top fill it, in the old Kayfun manner.
Moving the air flow around to one of the de-tents works,
if you remember to turn it upside down when you reopen the air, (little or no flooding).

Flavour, it is close to the K4, if like the T34 tank - a little rougher, but it gets the job done.
The favour level will depend on how open you have the air flow.
If you adjust the air down to the R91 level, you will get the same favour as the R91,
(slightly better than the K4).

Leaking, you can get some leaking from the air intake hole on occasions,
if you get sudden air pressure drop from a fast moving thunder storm for instance.
You can get some seepage under the air flow ring, when the collector is full,
Unscrew the 510 screw, then the collector & mop it out.
Screw the collector back on tightly, then the 510 screw.
Always unscrew the 510 screw before you unscrew the collector.
See: What Not To Do With The Russian 2.0.

Of all the Kayfun clones, (up to the K4), the Russian 2 is the best.
I'm sure SvoŽMesto sat back after making the K4,
looked at all those o-rings & how tight the tolerances were,
and then though - NOW CLONE THAT YOU BASTARDS !!!
All of the K4 clones leak.

Note: I will get to a Russian 3 review at a latter date.
Suffice as to say, it's a fantastic vape with lots of problems.