What is the profit in resolving the issues with Ulysses peacefully at the end of Lonesome Road? Other than not having to fight him, that is? (the loss is I won't get his unique gear)
Fallout wiki suggests the following:
- If the player chooses to spare him, after the quest The End Ulysses will hang around near the entrance to the Canyon wreckage, where Ulysses will help the Courier make camp fire recipes. Ulysses will also present new dialogue options, such as giving hints at how to deal with Legate Lanius and commenting on possible previous player actions in the Mojave (e.g. killing House).
- Ulysses will also supply the Courier with miscellaneous items he found in Hopeville (The Courier's Mile), including rockets, Rad-X, RadAway, MRE, and pre-War books.
- If he is alive at the conclusion of Lonesome Road, he will offer both the history and recipes of bitter drink.