The blu is a relabelled e9, I think, along with the 'red dragon.' Similar to the VK, KR801D-1 but not identical.
HK45 made some good points - if there was but *one* answer for everyone, really, wouldn't we all have the same one?
And yes, parts fail, some people seem to have attys last forever, others get DOA out of the box, or batteries fail in a week, while others go on 'forever' (relatively speaking, in e-cig land that seems to be 2-3 months
).
First week: 401 atty failed, with minimal use. 2x auto 510 batteries failed with 2 days of moderate use. 1 401 charger DOA out of box. Conclusion: BUY A USB PASSTHROUGH!
(or build your own, or buy an SD/like device)
Got the KR801D-1/VK etc today, from cigeasy, who had the best prices and in stock at the time, good packing and shipping. Compared to the M401 and 510, it's interesting. Limited use so far, but at first look:
- roughly 5mm longer than the 510. Insignificant size difference to me.
- same diameter as the 510, which is IIRC ~9mm-10mm, which is ~ 1mm thicker than the M401, with the M401 being quite close to an analog cig.
- I'm unsure I like the metal carts - under the sticker on the cartomizers, it's metal, no 'squish' like most other carts. I may try some shrink-tubing on the end, as I tend to bite and squish the ends on analogs and my e-cigs slightly. Is better with the sticker on, but I expect they may come off with attempted multiple refills.
Only comparison I can do right now is vs 510 or M401 refilled (36mg), a 16mg High Mboro for the 510, versus a 36mg cola 'freebie' (thanks
), or some 16mg m'boro on the VK/KRD..
The 510 on USB, or manual battery, with 16MG MLB High (which AFAIK = 16mg). The M401 with refilied RY4, and the KRD with 36mg cola 'out of box.' I'll do a more apples to apples when I have some free time and refill a few cartomizers.
Draw: I like the 510 manual battery best, it's closest to an analog, has some resistance. As it is, I still cover 2 of the 4 air holes on the atty with my fingers at times, likewise on the M401 and VK (KRD.. = too much typing, but it's not a VK 'branded'). The draw (uncovered) on the M401 and VK are similar, I go back and forth, on which I prefer. Both are easier to draw through than the 510, which for some, may be a good thing. Covering two holes in each, it's 510 > M401 > VK, in order of most to least resistance. During this testing, the 401 draws a bit more like a real smoke resistance-wise, the VK is too easy of a draw for my tastes.
Vapor and throat hit:
Again, note it's not entirely apples to apples here. The 510 I can check with my 36mg RY4, M401 the same, the VK with a 36mg Cola cart from cigeasy, or a 16mg cart (none refilled yet for the VK) only.
All are based on a 5 second, reasonably slow draw, preceded by a 3 second 'primer puff' to make sure atty's warm and at least some fluid's flowing. Before that, each was vaped 'regular'y for at least 2 minutes each to ensure the cart and atty were ok. Batteries are charged, but may not be 100% charged in all cases (charging station has too much stuff plugged in right now), will re-test on a weekend when I have time.
510 16mg mbo high, manual bat: decent throat hit, good vapor production. Throat hit: 7.5, vapor 8
510 32mg RY4, manual bat: slightly better throat hit, good vapor production, for some reason slightly less vapor than the first 510 (could be lower bat charge, perhaps). Throat hit: 8, vapor 7.5
M410, auto batt, 36mg RY4 refill.
Throat hit: 6 vapor: 7-7.5 (new atty, primer burned off, from eastmall.net) Less throat hit than the 510, but a good amount of vapor!
VK, auto batt, new 16mg MBO High: Throat hit: 6.5, about the same as the M401, vapor: 7.5. Consistently produces the same smoke as a good vape off the M401.
VK, auto batt, 36mg Cola: Throat hit: 6. Sometimes consistent with the other VK and the 401, sometimes a bit less. Vapor: 7.5
The 510 and VK are more consistent by a bit than the M401, and the M401 has significantly smaller carts, I'd say ~ 1/2 the size of the 510 cart. Note that the VK are 'out of the box' carts, and many seem to say once you refill, they produce better throat hits and vapor.
Favorite in house: 510 on manual batt or passthrough.
Favorite for light travel/in car - M401, mostly because both my auto 510 batts crapped themselves within 2 days, and the 401 cart I can bite on a bit to keep in mouth, it is closest to 'real smoke' in diameter. Carts need filling more often, though.
Convenience: The VK. Easier to pack up with the 2 piece. Battery life *should* beat both the 510 and 401. No spare attys to deal with, just a few carts.
Likes/dislikes:
510:
Likes: best throat hit, best vapor. Manual batt performs well (hits/draw, unsure on batt life yet)
Dislikes: auto batts are crap. Even when working, they weren't comparable to the passthrough or manual batts. I'd like it to be slightly slimmer, or a slimmer/tapered mouthpiece. 'Hidden' atomizer (I don't drip, but dipping is very nice/safe/easy, let the wick do the work..).
M401:
Likes: Most 'feel' like an analog. Good e-cig all around. Has an exposed atomizer, so can be dipped very easily.
Dislikes: Few, really. small cart size. USB passthrough is hard to get. No manual switch batteries AFAIK. The auto batts go off easily unintentionally
VK:
Likes: convenience. Likely batteries last longer, carts last longer. Don't need stock of attys on hand. The auto batts don't go off unintentionally like the M401s.
Dislikes: Can't get blank carts to fill from own fluid from start, so some combos could become nasty. More expensive carts. Non plastic mouthpiece.
'Perfect combo' - the 510 in same diameter as the 401 would rock, with manual batt, plus USB passthrough. Oh, and a softer mouthpiece.
Conclusion: There is no 'perfect' e-cig yet
May revise later, once I can empty and fill some VK carts, and set up 2x of each, with same fluids, fresh charged batteries on all.
). It's a money pit but if you were/are a heavy smoker (two packs a day here) the cost comparison isn't that far off and I'm more than happy that I've lost analogs, nasty smelling clothes, hair, and breath, burn holes in practically everything I own, not to mention the whole politically incorrect, irresponsible social pariah sort of thing (although people still don't seem to like me any more than usual 
