Does ue4 support only VS? How about QT?
UE4 is just C++ so it should work with any C++ IDE. Note: VS Express is 100% free and you can get VS Ultimate for free if you talk with MS about Bizspark or Dreamspark.
Answer from the wiki: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums
Qt is cross-platform 