Not great, but you get used to it.
Yuck, the smell/taste of hydrogen peroxide reminds me of ickiness… Perhaps because I’ve always associated it with cuts and scrapes but to me, it tastes like how I would think wounds taste. Gross.
If you don’t like the burn of Listerine, get some of the newer Crest Pro-Health rinse. It uses CPC instead of alcohol so there’s no unpleasant burn (just a slightly unpleasant aftertaste but you get used to that too).