Marmite is stronger and more coarse in flavour and texture than Vegemite. Vegemite is stronger and more coarse in flavour and texture than Promite.
Promite takes the prize. It's much sweeter than the others, too. And less salty.
Yep, the trick with Vegemite et al is to use them sparingly - a thin scraping. And it's not a taste for the sweet-tooths amongst us. That's why we give it to babies from a very early age. Helps keep the dentists a bit poorer, as the kids don't develop a sweet-tooth. Well, that's the idea, anyway!
Vegemite is a great gravy-browner. If you want your stews to have a nice brown gravy, add a teaspoonful or so of it.
If you're partial in winter to a 'beef tea' as a hot drink, flavoured with salt and pepper, you can use a teaspoon or so of Vegemite to a cup, and top up with boiling water. Stir well. Supposed to be a good brew for an invalid, like gruel.
It's very high in B vitamins. It was fed, on their release, by the jarful to Australian (and other) soldiers who had been starved in Japanese prisoner-of-war camps during WW2 to treat beri-beri. Worked a treat.