Better use one that operates worldwide and for a long time. Generally they are safer and more trusted, and offer more fiat pairs. As a few options you can check CEX.io, Gdax, Bittrex.
I think it'll continue to be used as an asset. It's not suitable for paying for goods and services. It's way to expensive. Agree. I do believe that bitcoin is a part of financial future and great way to become an investor, but I have doubts that it can possibly replace traditional money or become w...
IMO Bitcoin is an undisputed leader, because of its profitability. Then comes Ethereum.
But it's only from my point of view. Each investor should make his own decision based on personal financial capacity, strategy and expectations