Part of the reason some people think mushrooms taste the same is because many common supermarket mushrooms in the west do taste similar.

In particular, three of the most common western supermarket mushrooms (button, cremini, and portobello) are actually all the same species (Agaricus bisporus). They just look different.

Shiitakes are a different species and do taste different, but are somewhat related; at one point in the past they were classified in the agaricus genus.

Once you venture outside those, tastes and textures rapidly diverge. Truffles and morels are definitely memorable if you've never had them before.

They taste wildly different. Just like not all fruits taste the same. Or all veggies. Or all meat.

My personal favourite is Chanterelle. Yellowfoot is pretty great too.

It's the only kosher mushroom.

Any way you can expand on this? What would make a mushroom non-kosher?

It has lowest change of having worms inside which are not kosher. Most other mushrooms needs checking if it's not worm-eaten.

Button are the most bland 'tasting' mushrooms, but you can find them in any shop because they are easy to grow in artificial conditions. There are so many quite strong tastes in the mushroom world, that some were/are used as spice. But its same as with forest fruit - those growing in wilderness have much stronger taste.

The strongest ones I would say are morel and of course truffles which are used for finest (and most expensive) delicacies, but many others which are more common are great too.

To experiment, find some chanterelles, lobster or porcini, and shitake mushrooms. These should be available fresh or dried in many large groceries in bigger cities. Make some dishes with each or try a taste.

Huge huge differences in mushrooms.

My favs are chanterelles, chicken of the woods, and candy caps (which have a distinct maple/sotolon flavor).