The best cryptocurrency to invest is bitcoin because it seems it can be even only winner in the very long term. Other ones are very risky, privacy ones can be threaten by governments.
In my opinion the best cryptocurrency for investment is bitcoin. Because of it price which is too high then that of other cryptocurrency. Bitcoin is also accepted by many big multinational companies which help to increase its market price and also help it to increase its investor number. Although its a highly volatile currency but it is perfect for short term investment purposes. But it is risky also. In the other hand people who want long term profitable investment, they should try Ethereum. Their are two reasons behind this first it is less volatile and second its price is also good and profitable.