Don't say maybe. Flip that word to definitely. @theanubisrider and I are actually doing most of our dev work in Unity, but we are engine agnostic and just use whichever engine fits best at the time based upon type of project, resources we have, and time. We own a ton of assets for Unity and some of them we could get into Unreal if we need to. I have no doubts we'll possibly use Unreal on some future projects.
@theanubisrider has messed with importing characters and such into Unreal as we were considering using it rather than Unity on one large project. It was ultimately time to relearn some things, and a lot of assets (like particles) that would not simply port over to Unreal that made us stick with Unity.