The E1 is a pretty different beast than the E2 and E3, and although *popular* opinion tends to lean towards the E3, I personally tried every horn in the Adams room at ITEC and loved (and ended up buying) an E1 over all the others. It's an EXTREMELY flexible and responsive horn, and depending on your playing level, I don't think there's anything you wouldn't be able to do with it. Honestly though it's like everyone on here says - it's all about what's the best horn *for you*.
Sean Kissane
Low Brass Specialist, Paige's Music
Principal Euphonium, Indianapolis Brass Choir
Principal Euphonium, Crossroads Brass Band