I recently tried vegemite for the first time. I was at a B&B at the time, and the owner advised me of the "correct" way to use it, so I didn't make the same mistake as many others have done in spreading it too thickly. So I just had a very thin scrape on a piece of toast. To me, it just tasted...salty. I couldn't really get much of a read on it other than that. When I said so, the B&B owner said, "Yeah, that's essentially what vegemite is. It's salty."
And it was pretty dang salty even with just that thin scrape, I can imagine the unpleasant surprise that would have awaited me if I had spread it on like peanut butter. The B&B owner told me a story of someone who mistook the brown paste for chocolate and actually put an entire spoonful in his mouth at once. Poor guy.