the 801 Mini is great for flavor, 510 most popular and a good one to try as is the 901, they are all good and serve there own purpose depending on how you like to vape, its all very subjective, what one may like another one may hate, just try them all over the course of time. 510 like I said is most popular and a good place to start, as is an LR-510
My goodness, mwa! At 155mm, the 801 is a
penstyle,
not a Mini (such as the 112mm 510, 117mm KR808D-1, or 118mm 901). I do agree that it is great for flavor ... and that it's "all very subjective."
I'm not familiar with the 302D, but the Joye 302 is an 801-compatible penstyle (as is the Boge JKY302).
All that having been said, these lengths as based on the atomizer connected to the battery for which it was originally designed. More often that not these days, these atomizers are connected to other batteries, e.g., the Joye 510 (or its many "510" clones) often is attached to a fat batt like the eGO or Riva.
As has been mentioned, the threading of the 510 and 306 atomizers is identical and they are compatible. The 901 and Kr8 threading is identical, but the airflow is handled differently, so a Kr8 cartomizer will not necessarily work on a 901 battery (or 901 mod fitting). [The 901 atty will always work on a Kr8 battery.]
The manual 510 is a good model to start with, although I recommend two others instead, depending on personal preferences: either a 510-based fat batt (e.g., eGO or Riva) or Kr8. See
my article. The best (and most expensive) Kr8 is the Bloog MaxX Fusion, which I
reviewed a few weeks ago. Without knowing anything about the individual, this is the model I would recommend to the current smoker. [And it is one of
my two favorite e-cigs, even after two years of vaping.]