We,ve been lucky, our friend is a 55yo semi professional iron man, who trains around 4 hours per day, has a very strict diet and drinks plenty of water.
I have swallowed a lot of cum in my life over the last 35 years, icluding a lot of my own, and hands downs, his cum tastes better than anything i've ever tasted. The very first time I licked his cum off my wifes ass cheeks, I couldn't believe how it tasted different from any i'd tasted before it, was actually quite sweet, and has been for 4 years. So diet, exercise and hydration is huge along with very regular ejaculations.
So for me, they all have tasted similar aside from his, but I thik smell really adds to how it tastes as well, if the smell of anothers mans seed turns you on (it drives me wild) then you'll enjoy it no matter what it tastes like.