Litecoin is a good coin but we don't know that how long it is going to last long because more and more altcoins are replacing the place of old altcoins just with their initiative ideas or simply promoting on the social media with popular individuals. So litecoin may survive or not in this race in long term means the decision is on your hand and no one knows what can happen in future.
honestly i still believe that for the next 2 years litecoin will still be in the top 20 of the coinmarketcap
But two years isn't actually a long term investment, it should be atleast 5 years then only we can get enough profits in year averaging. I too agree that litecoin may survive in the top 20 position but with the increase of cryptocurrencies and new projects the market cap value of litecoin is going to be same or lower not so much higher.
With many new alternative coins, positioning of those coins inside top 20 is not stable,
We don't know if how each coins will perform in the next following years to come, I like Litecoin as alternative but investment wise
if aiming for bigger profits, either find of new initial offering or ride with the hypes coming from those assets that performing and
gaining community support.