I often take meat-eaters to vegan restaurants in Melbourne, and for fowl (chicken and duck) they say they can't tell the difference between the gluten-based ones and the animal flesh ones. Some of them have said the best fried chicken they have ever had was at a 100% plant based restaurant.

Red meat is a bit harder to emulate though there are expensive ones like Impossible Burger and Beyond Beef that do well. Many other substitutes cope better in heavily cooked dishes like ragu or lasagna than burgers or sausages.

Tastes are different. Frankly, I've been vegan for around 5-6 years by now, so I might also not remember the "original" tastes of some products. Still, I'd imagine there's not much of a difference for many a product. Vegan cheeses can be a little hit or miss when it comes to taste - that's where I notice it the most.

Most meat substitutes, think patties or minced meat or some vegetarian butcher products, taste absolutely like they're animal-derived - no contest. But that's the case for Germany. Not sure what the situation is like in other parts of the world.