They are definitely slimy but not at all fishy - I've heard people say that too and it put me off at first, then I got a pack and there was no smell at all. They come stored in saline type stuff so you do have to rinse them before use.
They're not a pasta noodle, they're a fibre, the root of a yam plant, so they're chewy and don't taste like regular pasta. I've found two ways of cooking that either dry them and make them easier to eat or soak them. So if I want them soft I boil them for 10 min, then pour out the water, pour in beef stock, a drop if soya, add spring onion, simmer that for a while, then add meat if I want it and eat it like a ramen soup.
Last night I rinsed them, microwaved them on high for 7 mins uncovered, then melted butter and Parmesan in with them and a tiny bit of spring onion.
They're not great with Italian type sauces although I have them with cheese sauce sometimes as it coats them well.
They're not a low carb fad, they've been eaten in japan for a long long time. They're quite heavy is the stomach so I don't have them too regularly but they're useful when I need something quick or my planned meal has gone off (like my cauliflower did last night).