This is a tough one and I think it will depend on a number of different factors including each individual child and each teacher. I would initially suggest speaking with staff at the school and seeing how they directly handle advanced students as well as trying to find a few parents with first hand experience.
FWIW we are leaving a private school and switching to an e-school next year for DD9 who will be in 4th. EM has been a huge issue for DD since K. Each year was a bit different as it would depend on the teacher quite a bit. Some would supplement, some wouldn't. Even though they also have a math pullout program 2-3x/week using Singapore it still wasn't enough for DD. Math is her passion though, and she desires to switch because of it.
In theory I like EM, but it is a very poor curriculum match for both our kids. It is incredibly repetitious and works off an assumption that mastery will take a very long time. Our kids don't need the built in review which comes with each unit. DD has huge issues with this as well as how slow it moves even when introducing new concepts. I've pulled up links and EM curriculum quotes before if you'd like to see them I could track them down again.
I'm trying to be diplomatic here because our situation revolves around EM and we're leaving what should be a great private school in large part because of it. That said it would take a lot of convincing for me to believe that an advanced child appropriately placed in EM wouldn't still be bored to tears with it based solely on the pace. Someone prove me wrong, please!
