Guns, Dogs and Blades QnA

Sublime one said
The B8s are much easier and frankly I prefer them As my go to target for all things, But students do not like them.

They are my go to as well. It seems like a good standard for pistol out to 25 yards. The bullseye creates a decent sight picture and is not too large and not too small for either 6 o'clock or POA.
What don't your students like about them?