One of the interesting things about all these direct inhalation brands is the addition of a turbulence hole (which must never be covered) between the flame intake and the bowl. The addition of ambient air before reaching the bowl (and after flame intake) is probably the best thing about this design. This agitates and cleans butane compounds still present from the heated air via the intake. So, there's less risk of combustion and more homogeneous heating (with fewer harmful particles or parasitic tastes (depending on the type of butane used)). The carb hole after the bowl is optional and depends on your preferences (this one can be closed completely with a carb cork but personally I like to play with it). It seems to me that only Triihouse, Sticky Brick Labs and Dreamwood add this turbulence to their designs?
Personally, for about two years now, I've been using Clipper brand (Flamagas, Barcelona, Spain) 100% premium I(SO)-Butane (Clipper Pure, refined 12x that ensures clean/complete combustion is residue-free, 98% I-Butane, 1.60% Propane, 0.38% N-Butane and 0.02% others..) and I've never tasted butane or gotten a parasitic taste (and yet I'm very sensitive). I personally find it purer than the Colibri (Unitask NV, Antwerp, Belgium) because I think this one smells really bad (54% N-Butane, 24% I-Butane and 22% Propane). However, in comparison, it seems to have a slightly lower calorific value (heating power) due to the very low Propane content, but this does not seem to be a problem for our usage with bricks (quite the contrary). My torch lighters are in excellent condition working. To date I've only tried Colibri and Clipper Pure.
In the USA, many options are apparently available? such as Puretane (99.9998% N-Butane and 0.0002% I-Butane) triple refined by through fractional distillation, 11X filtered (to remove every last possible impurity), seamless aluminum cans (eliminates all toxic manufacturing lubricants typically required for welding seams) in a food grade canister (BPA free plastic lining, protects against corrosion on the interior of the can), clean, colorless and odorless.. but here in Europe the choices are very limited..
The only disadvantage of bricks for me is that you need good eyesight (especially outdoors or on a very sunny day) and no trembling (and also that you need both hands to play properly). You must be relaxed and accept the ritual.. It's not a vape to be used at alcoholic parties either.. Instant draw flame vape is something magical