America: you’ll be close to home, avoid the hassles of traveling, no language barrier, your family can come visit you/you can go home for shabbos and chagim.
American sem, pros: Affordable, parental supervision, less chance of getting into trouble (ex: going to clubs etc..) Less chance of spiritual regression.
There are different types of sems, to the best of my knowledge, in EY as opposed to the US- the ones in the US seem to be overwhelmingly Bais Yaakov as opposed to more of a variety in EY.
My cousin went to seminary close by and was home for Shabbos once a month and all of the yamim tovim- something that was important to her.
Then again, Eretz Yisrael is just, well, Eretz Yisrael…
Right but not everyone is able to go to Israel nor is everyone ready for it. I would say that if you are in new york you should for sure go to a seminary outside the tri-state area, but if not Israel, maybe Toronto.