Both work well. The best option is not to choose one of them, nor to choose two of them, split your money with different percentages; put some of them to ETH, some LTC. I prefer ETH more because it is coin more comprehensive than LTC. In addition, ETH can be used for a variety of purposes. Most ICOs use this network for their smart contracts so it is checked for quick transactions. I also have a lot of tokens in the ETH network.