are ceramic bearings worth the cost??

For what use?

As clutch bearings I would say NO.
For engine bearings probably.

They'll last a bit longer as clutch bearings but no huge inscrease of life.

do they run smoother than normal bearings or is the differance not noticeable?

They last longer than all of the other bareing and there alot smoother. I have a set in my CRT diff...

they are great if you race or love high performance. they are too expensive if you nly bash.
they defiantly are much smoother

i love high performance. (still havent found anybody who dosent) i guess ill prob get some when its time for a rebuild

there great for high performance and can withstand a higher amount of heat, they are really good but expensive, but if you not serious about racing and just local racing or just bashing then dont get them.

Ceramic bearings are pretty much superior to steel bearings in everything except cost. They are lighter (less mass to spin), conduct heat better (absorb and release heat faster), harder (more durable), and rounder (spin smoother). For me, I wouldn't run out and get some for a new motor, but when it came time to rebuild my engines I went with Ceramic bearing (front and rear). I used Boca and TKO brands, and have had no issues. I wouldn't use them in the Clutch bell unless you plan on tearing it down and lubing it after every run.