Ripple is a good investment if we look into the use case part. Many institutions are also supporting it which makes it more reliable in long term. Litecoin, utility wise isn't really a great option. So, if you have to choose only between Ripple and Litecoin, I would suggest you to go with Ripple. But I actually not a great supporter of both in long term. I would still prefer our good old Bitcoin when it comes to investment for a year or more than that.