BBQ Bandit, will you expound on the plusses and minuses of each as you see them?
Please take the following with a grain of salt. Have only had these last two smokers (Lang 84/Klose BYC) for a few months... and still learning about it. The comments below are just on the configurations, sizes, and styles that I have. These are not the only answer, just one person's observations. YMMV.
Both smokers (main chamber) are made out of 1/4" steel.
Both smokers are over 1,000 lbs... altho not on a similar size.
Both are stickburners.
Klose offers 1/2" steel firebox as an option, Lang doesn't.
Both have options for a warming box;
* Klose's vertical chamber is opposite end of the firebox (coldest zone)
* Lang's vertical chamber is directly above the firebox.
Lang is a reverse flow... which is a full length baffle running under the grates from the firebox... meaning the smoke and thermal energy runs under the baffle (right to left) warming the baffle. The side effect is that baffle becomes a source of radiating heat... minimizing hot/cold spots. Once the smoke reaches the left side of the chamber... rises above and returns (left to right) over the meat before leaving thru the exhaust stack. The tell-tale indicator is that the smokestack is right next to the firebox, not the opposite end as in a traditional offset.
The Lang and Klose configurations that I have are without a trailer axle.
There are trailer configurations available for both.
The Lang was modified by a third party; adding larger wheels... intended to be softer ground/surfaces for mobility and is a comp ready smoker. Rolled and maneuvered on grass without a problem. (The smoker came standard with smaller steel casters... not intended to see anything other than paved roads or a concrete patio pad.) The larger wheels allow me to roll in/out of my trailer using a 12 volt winch and strap down to transport onsite.
The Klose had 6" caster wheels installed (option) and has seen competitions in its previous life (Poobah). Would be worried seeing soft ground. (Klose was moved by myself... however laid down 1/2" plywood (3 sheets) end to end to distribute the weight of the smoker. Not advisable without proper preparation.
Costs;
Found both models used and well taken care of... reducing the impact of the overall cost.