Does anyone use them?
How are their sound?

Are they extremely different from a regular metal mouthpiece?
I am thinking of experimenting with a 1.5 C crystal clear, but not sure whether or not it will be even worth the 20 dollars.

Are they serious mouthpieces or more like toys?

Thank you for your opinions.
Really helps me out :D

i bought a nice green 5C about a year ago and played on it for quite a few months, it was really comfitable, was always warm so its amazing for out door playing etc. the thing about that tho is your not always 100% sure when uv warmed up which is always a bad thing and there not as well made as the metal ones, persoanaly i prefer metal ones after playing on both, but the plastic ones are only around £10 compared to £40-50 for a new metal one. go into a shop and try one and see what you think.

I bought one,
I can't wait for band practice to start so i can try this out on my trumpet.

(I only have a cornet at home)

What surprises me is that it is super light weight, I did some buzzing exercises on it, for some reason, it felt very comfortable.

And I dont know if im imagining it or not, but is the bore slightly lareger than a regular 1.5 C?

Thank you for your input.
I will keep you guys informed to help others out. :D