Pangong tso located in Ladakh at an elevation of 4225m high is also known as Nyak tso. Surrounded by fresh water of the lake, filled with acquatic life, ducks view are very popular here. The weather in July dips to 20 degree Celsius. This spot is popular for trekking and camping. Tso moriri is yet another popular lake nicknamed as Mountain lake, located in Ladakh. This lake falls under Himalayan lakes division, which is very popular for cranes, and a few carnivorous animals too. This spot is an exceptional trek spot, for the elevation crosses 5400m. Since both the lakes are 8 hours apart, if you could plan both you make great travel memories. Since both lakes are great to visit, I would suggest you should try to visit both.
Both lakes are totally different experiences but are equally beautiful. Pangong is more commercialised and easy to reach, while Tso Moriri is very less commercialised, and the way to reach Tso Moriri is an adventure in itself. You'll need 2 extra days for Tso Moriri because you'll have to stay there a night. If you like quiet and offbeat experience, then do add Tso Moriri in your Itirenary. If you consider beauty wise, both are almost on the same scale.