[B]ive had this for a long time.it was just sitting in my closet because the Roach cover that i was using at the time was doing just fine.
well about 3 months ago i got a trials uni and i didnt need the weight,padding or lust of an air seat so i took every thing apart,stuck the foam in the new Gemcrest cover and mounted it to the seat base.
the sides of the Gemcrest are not as tall as a Roach.its only about 3cm taller than a Miyata seat cover.thats why i stuck with the super tall Roach when i was into MUni.unless they make the Gemcrest widely available in a taller model I belive that its better to use a Roach or REE-cycle to get the true cushiness of 2 layer air pillow action.
BUT HEY! if you only want to use foam or one 12 inch tube instead of foam this baby is real nice.im using it on my KH20 (now known as the Pro model) with only foam.it holds its shape looks nice and feels like leather feels 
like a well fitting glove.
the thicker material also feels better in my palm durring seat out hoppin.
this is a seriously nice upgrade for someone who doesnt want a cheap Miyata seat cover but also doesnt want tall sidewalls and alot of extra material because its not stuffed full of foam or gel then jakked full of air.
saying all that,its would make a nice MUni seat cover to as long as your content with a single layer.
the down sides are as follows:
dont let it get wet.i live where it rains alot,so putting a plastic bag on the seat while not riding but while outside is not uncommen.
uni.com touts it as being there most durable seat cover?i dont know about that.leather does rott Cordura doesnt.
uncontrolable sniffing of the seat may occur.English leather is worth $40!
im happy i bought this product. [/B]