I noticed a big difference. I purchased a Green/Yellow RSX Trail, and then added the 2.0 shocks, steering wheel, front bar and a few other goodies to make it a Sport.
So I did get some riding in with the original monoshocks and then after about 10 hours installed the 2.0's.
I like them much better, more freedom to adjust based on terrain, etc
Are they worth the $1800? Depends.....
There are not a lot of other shocks that will bolt onto the RSX that are comparable, so in my opinion, they are the best bang for the buck based on what is available