i use an Edwin Jagger myself... and started out, like you, with derby's.
As a combination, it didnt work that well for me... shaving rash, bumps and poor shaves were typical.
I went through a phase of trying feathers, and although I like them, found them too aggressive for my sensitive skin, without any real benefit.
In the end, my compromise, and by far the best blade ive ever tried in a EJ razor, is the persona. Closely followed by the gillette platinum. But the personas are easy to come by, fairly cheap, and consistently give me superb shaves over a good 3-4 uses. Not as crazy sharp as feathers, but much sharper than derby's and smoother than either.