This  is a very complex question, and it’s next to impossible to give a  definite answer. The reason being all of these have their pros and cons  and virtually no one can give you more than a speculation. Here are the  main points about all of these currencies:

Bitcoin - even though it’s not the very first currency out there, it certainly is the most popular and successful  as of now. The market cap is way above all the other ones. It is often  referenced to as digital gold, sort of an asset that gained enough  momentum that it will remain valuable for time to come.Having said that, this does mean that the network is overloaded  leading to major delays in transfers, it has many major governments  trying to regulate (and often limit) its use, it became next to impossible to mine and the price of coins as well as the transaction fees are way up there, so much so that it hardly makes sense to invest if you don’t have rather hefty amounts to throw at it.

Ether  - Made using Ethereum, this currency has seen more than impressive  growth. As of the beginning of 2018 it successfully surpassed 4 digits  USD value for a single coin. The main advantage is the use of Ethereum on the backend,  which is now used by many others to build blockchain based  decentralized applications. It is way easier to understand and learn  than the code behind bitcoin. For this reason, Ethereum has relevancy  like no other and is being used by many institutions for all sorts of  things.However, since the code is very young and decentralized, it is prone to bugs  that can be pretty detrimental when they occur on big transactions.  Also, the main thing that gives Ether the advantage that it currently  has, which is the fact that it’s build on Ethereum, might be taken away  from it if another, even more user friendly platforms occurs.

Litecoin - It was made with the idea of it being a better, faster version of Bitcoin. It introduced features like SegWit and lightening network, which were supposed to make the transactions faster and cheaper.SegWit has been introduced to bitcoin blockchain as well, so the gap between the two has become somewhat smaller. Litecoin doesn’t really suggest any new ideas (like most altcoins), but rather refines the one that are essential to bitcoin.

Ripple  - Ripple, on the other hand, does introduce a significant change. It is  used for fast money transactions and as such has a lot of appeal to major financial institutions. This is something that makes it somewhat more stable and less prone to fluctuations.

It is not a cryptocoin in a traditional sense since it is mostly used to back the money transfers. Also it is way less decentralized since the company that made it owns over 60% of all coins.

So  options are there. It is worth noting that it is a very common practice  for people to not invest in a single currency, but to build portfolios  of a few of them. Also you can always exchange one currency into the other. As long as you compare the rates and make sure you’re getting the best deal, that shouldn’t be a problem.

So there is no real answer if you ask me but what do you think please comment down below.