Bit-- first of all, betting on poly and making figures for it are two different things. Betting it, for me, has been tricky, where figure making has been pretty straightforward-- I do it the same as for any other surface. I made no assumptions about it staying the same speed, and in fact have found that it is more changeable than dirt, which may have to do with shade/temperature changes that cause contraction of the molecules. Or not. But it definitely changes.

Grass horses definitely handle synthetic tracks better than they handle dirt. But all that means is that you have more "data points" to work with in a race-- to oversimplify, you make figures off the horses who run well in a race, not those that throw in "X's". I had no preconceived notions going in about how horses would handle the surface, and don't look at what they have run their prior figures over when makling the figures. I do when betting off them.