2 months ago I asked the ladies in TVAL if there was any mandate about mounting/running TK or Carrier units on new or existing straight trucks. They laughed. Said, yes, they had heard the rumors too. They said there is no truth to the rumor. It is up to the owner entirely. This was from Brenda and Dawn. Recruiters can be liars. Make them show you the mandate in writing in the lease contract......it isn't there.
As for preference.....the Carriers use some outdated design and hardware in their units. The TK units are very intelligently put together....but early on, they had their share of problems about 2 years ago. As for comparisons, Carrier still uses brushed DC fans in the evaporator. Brushless DC fans have been out there since the early '80s, very reliable and powerful and durable. TK uses brushless, Carrier still does not on all units. Carrier uses a heavy, wonky, empty motor housing just to connect fan v-belts to the fan for the condenser. TK doesn't. TK pays attention to the routing of cooling air in the evaporator unit (the heart of the unit's ability to remove hot air from the box) while Carrier carelessly does not. TK uses a microprocessor that teaches itself how to keep setpoint based on changing outside air temps and as your load changes.....Carrier uses an old, obselete, preset system. Just some of the differences I came across. I drive a Carrier; reliable if you know how they operate and watch the technicians like a hawk when the units are being PMd. Also, mine is a belly mount---I made modifications to it that make it remove heat faster than nose mount units, but cleanliness is a huge issue...TK units have a great chance of working great.
In my previous life, I was a maintenance engineer and designed many chiller units, for chemical processes and heat treating automotive castings.
Hopefully Carrier will get the lead out of their engineering pants and upgrade their units soon....