Basically, it’s not as expensive so gets some snobbish remarks like the sumo wrestler one.
It’ll have less adjustment, so if you are going to use all the knobs and dials and get it spot on for you, it’s worth spending more. A lot of people don’t really bother doing this though.
Also, the plushness talked about above might just have been the TK needing a service (It might have been something more subtle relating to damping though).
I have to add balance and say one of my mates is quite skinny and has some cheaper Rockshox (not quite sure of the model) which lack rebound damping adjustment. They feel overdamped for my preferences and I’m 4 stone heavier, so I can only imagine that they’re holding him back a bit. This can be sorted out by swapping the damping oil, but not quite as straightforward as twiddling a knob.