I had a Bokar utility knife that I used for about 10 years mostly at home. It was as sharp as the day I bought it when I dropped it and it broke.
Probably just a typo -- if so, forgive the correction -- but it's Boker, not Bokar.
If you got 10 years of frequent use without any wear at all, you're the exception to the laws of physics then. Ceramics do get dull. They don't get dull as fast as steel knives, but they do get dull. They are also prone to chipping. Further, they are problematic to say the least when it comes to sharpening.
I dropped it and it broke is one of the other MAJOR drawbacks.
A third is the absence of adequate sizes and any real variety in profiles. They're pretty much limited to what the French call office and very small chef's. They're office is useful when you want a small knife, but small chef's are non-starters as far as I'm concerned.
Fourth, good ceramics are very pricey.
I used to use it for fruits and veggies as it wouldn't make them turn brown like some steel knives do. I miss it.
I don't understand the separation of "fruits and 'veggies'" from other food. Also I find keeping and maitaining special purpose knives for very common tasks to be a pain. The why of it is beyond me.
The off color is caused by one of two things. Either your knives are crushing rather than cutting or there's some sort of chemical reaction with the blades' steel alloys. It's not any sort of leap to conclude your other knives are either cheap carbons (SK4, e.g.) which haven't been properly patinated or neutralized (as with baking soda); or, more likely, they are simply dull.
I've used old French carbons forever -- most of them since when they weren't old and neither was I. The rare instances of the browning you describe only occurred when I already knew the knives were well past time to sharpen.
Ceramics are something like Cutco in that they are knives for people who don't really "get" the whole "sharpening is part of owning knives" bit. But, to paraphrase Robert Knowles, they're entitled to cutlery too.
2 more cents,
BDL