Bitcoin will always be on top and we can't question its position. It has been very consistent and investors put their focus on it. Ethereum is following its footsteps but it still has to go through a lot. Ripple, Bch and other altcoins could be considered as top coins but their spots might change based on every market situation. All in all, nothing beats Bitcoin because it's the most trusted digital currency for now.
In this market, Bitcoin is the coin most held by people so this is the coin always in first place. I think there won't be any altcoins that can be compared to this coin because when people mention this market, they often talk about Blockchain and Bitcoin technology. I personally still choose this coin as a long-term investment because it brings good returns to investors and there is always a huge price increase on special events. Of course this investment is still very risky if you are not well prepared.
Indeed, you need to prepare yourselves for both possibilities, but if we are here investing for long term, its understood that we are also investing in the future of coin we are holding, most people invest in BTC because it's the most popular and the most profitable since its inception and they believe though it has already grew a lot, there is no stopping its growth since the supply is pretty limited.