Architecture wise, an in-house engine we built for the PS2/Xbox (this was over 10 years ago). But as an overall package (editor, visuals, code, etc) I do think

Architecture wise, an in-house engine we built for the PS2/Xbox (this was over 10 years ago). But as an overall package (editor, visuals, code, etc) I do think Unreal is one of the best out there. It isn't as simple to start working with as for example Unity3D, and the content processing for consoles used to be very slow, (and personally) not a fan of UnrealScript. But still, I've worked on an FPS, hack and slash and a strategy game with it. It is quite versatile and if you have access to source code (which you do now, but before with UDK only you didn't) you can do some amazing things with it.