In case you think LTC is dying... which coin recommend me to invest for a long term?
Perhaps you could check out Peercoin. Peercoin is a more balanced design, but it is more complex than both BTC and LTC which are almost identical except for block rate generation time and Proof-of-Work algorithm.
Both BTC and LTC will suffer badly in the future from Blockchain bloat and centralization of control due to ASIC mining. BTC blockchain is already huge and the coin is only five years old. I am confident it will never get to 50 years old and probably not 10 years.
Because of intensifying centralization of ASIC mining, both BTC and LTC coin holders have NO say in what software or protocol changes might be adopted or not. Surprisingly not even the devs have much say if new software changes are adopted. This is because increasing control is being centralized in the shrinking pool of ASIC miners and the even smaller group of mining pool managers. Thus, BTC and LTC both have within themselves different groups with conflicting interests.
On the other hand, Peercoin is truly decentralized. A full minting node can be run on a personal computer, or even a computer as simple as a Raspberry Pi. In the future Peercoin might run fully distributed on smart phones. There is no centralization and no divergence of interest as in BTC and LTC.
Peercoin's advanced design has many more beneficial facets but I don't have time to go into all of them here.
Good Luck, and Best to You.
NewMoneyEra