The tough part on here can be separating the facts from the opinions.
Facts...
Are they more expensive? Yes
Do they perform better? Yes
Do they last longer? Yes
Are they higher maintenance? No
Opinions...
Do you need them to win races and championships? Everybody has a different situation.
Are they worth the money? Depends on what your money is worth to you.
If you run pro kart tour, tri state, mid atlantic, etc., most of the real competition is gonna be on ceramics. It's not a coincidence that the teams that spend the money are the ones collecting the prizes.
If you are winning on a local level or just plain satisfied with your performance using standard bearings, you don't need to spend the money.
I ran standard bearings for two years and then switched to ceramics. I'm convinced. Here is why...
When I ran the standard bearings, there is no doubt that they would become sloppy over a period of several races. The trouble was trying to figure out what level of sloppiness was I willing to accept before deciding to replace them.
Of course the ceramics felt tight on day one. I can honestly say that after almost a year running them in two pro series, they feel just as good as the day they were installed. History tells me that I would have replaced the steel bearings 3 times over the same period. I don't find myself wondering if I can squeak one more week out of a set of bearings before replacing them. There seems to be no performance lost since new. If nothing else, the piece of mind of knowing is worth it to me. Jmo.
Based on my experience, I compare a new steel bearing to a ceramic bearing like this...
Both new, out of the box, is the closest they will ever be to each other in performance. Some may say they are equal at this point or at least the difference is immeasurable. What hooked me though is - the steel bearing doesn't just fail over night, it starts to degrade as soon as it starts to spin. Immediately the performance level of the two begins to spread. After 8-10 nights of racing it will be considerably different. This is where the ceramic bearing advantage comes in. The ceramic seems to continue to hold tight and certainly when it begins to degrade, the curve isn't nearly as steep of a decline.
My point is, when making your decision, compare a ceramic with 50 races to a steel bearing with 50 races.
Hope this helps.