I always look at the negative side so here goes.
Price per 200! And availability. They are far from a plinking pellet as silverback said. Ok for a target tarts requirement but would you consider them as a hunting alternative based on price?
More importantly ( disregarding the recent JSB quality thread ), how accurate do you need to be?
If your current flavour of pellets are spot on.
Let's say your using JSB's already. Your grouping whatever at whatever yards. No fliers your gun loves them.
What difference is a few thousandth of an inch going to make?
Shouldn't a "premium"