Its best if you own both. Both ltc and eth are great crypto and right now, they are performing well in the market. In crypto, its always better to diversify. It means investing in different coins. It will maximize your earnings and minimize your losses. Just like the saying says, don't put all your eggs in just one basket. Invest in as many crypto as you can.
I would rather just to invest my money in BTC and ETH because almost all of the trader known that LTC has increased too much now. I guess it will be not profitable if you invested in it. I am not saying do not buy ltc but in my own perspective, ltc growth is too much for a new buyer.