I would try it if offered, keeping a beverage of some kind handy.
The first time I had marmite I nearly gagged on it. Super salty kinda smokey flavor IIRC. I spread several large dollops on toast which was apparently the wrong way to serve it.
Once done right it's not a bad thing, actually kinda good but you have to do it right to even tolerate it. It seems the proper way to eat it is to spread butter on the toast first then swipe an incredibly small amount of marmite (about 1/4 as much marmite as you use to butter your toast, maybe even less). I still prefer jam but marmite will do in a pinch.
Serve with a beaker (mug) of hot Builders Tea with cream and sugar for the win.
My breakfast, or I guess brunch, most days is sourdough toast with butter and marmite, and a cup of builders tea. It's damn delicious!
) to compare with my other pickups.