I like the taste of precum and ... postcum always. The stuff that shoots out during orgasm has variable taste though.
It can taste (from best to worst in my opinion): a bit sweet (rarely), salty & good, flavourless, slightly bleachy, slightly metallic/coppery (not like blood tho), and really bitter.
I find watery cum to most likely be bitter. And morning cum is often watery. I like it best really thick and the texture doesn't bug me at all, and it's pretty guaranteed to be a good 'batch' if it's been a few days since the last orgasm.
That's all I've learned. I've heard meat, milk and asparagus make is taste bad, as well as fruit/pineapple makes it taste good.