Answer: Imperialism that doesn't last is better.
Step-by-step explanation:
Keep in mind that this question is very opinion based and there is no right or wrong answer (technically). However, I believe that imperialism that doesn't last is better because the imperialist country stops conquering land and forcing people out of their homes. Just look at the Kahn empire, (famously led by Genghis Kahn). He didnt stop and now about 50% of the middle east has some of his genetics becuase of how much he conquered. On the contrary, the United States had a bout of imperialism right after the Spanish American war and took over territories like Hawaii, Guam, etc. But the influence there was extremely minimal, becuase we ended up stopping. Hope this helps :)