I think polkadot is doing great and has good backup though $DOT doesn't have much fame but with time it will grow big and let's see what we come up with by the end of the year. Uniswap! I don't see any lack in the project surely it will survive but coins you mentioned has good potentials.
Uniswap and Polkadot in general are both good and just have to choose according to their respective tastes, because everyone who already likes a product will obviously choose it for the main one, the rest just look at the others, so please make your own choices in which.