I almost bought their bearings as a replacement ($15 ea), assuming they would be higher quality and last longer.

I have a Suntour - WTB grease guard I got in a trade , I use on 1 bike ..

Be it as it may; Ceramic might not provide much benefit in efficiency, but if it performs as equal yet can extend the useable life by a noticeable amount compared to steel, I'd opt for ceramic just for that purpose.

Ceramic shouldn't be susceptible to corrosion like steel. That in its self might indicate longevity over steel.

generally only the balls are ceramic and the races are still steel

I frequently pull seals and clean/regrease machine tool bearings. No reason you can't with a bike, though some seals go in and out easier than others. IMO, it should be dead smooth when done, otherwise you either didn't get it clean, didn't use clean grease or should have replaced it.