Yes I think that the biggest descrepencies we have seen in our travels so far and probably because of the fact that is the only moving piece of equipment is with various teters you just don't know what you are going to get till you see it work, some are slick or very loose and drop like stones and bounce back up like 5 inches, while others are stiff and slow, and the darn dog need to go a further 1 or 2 steps down the board just to get it moving, next to that it would be Chutes with differing fabric weights and Colours a dark color really messes with him, followed by as you say contact equipment condition and grip surfaces going from sand paint to full rubber to full carpet.
WE had one teter where Cosmo ran up the teter to his usuall tip spot, nothing, took another step nothing, again nothing, I am standing there going com-on com-on and then it just sort of released & dropped like a rock on him like it had been stuck up, it very disconcerting for him and necessitated an entire practice session at home on our usuall equipment after the trail to get him settled with it again, I do know that the AAC judge mentioned it to them as well to get it fixed before the next trial and she pulled it from a couple of courses later in the day where she could. It was pretty bad.
