I have an EA mod, which had been sitting idle for quite some time, because I had disassembled the side button switch one day, and broke the little E clip that holds everything together. Terrible design, especially for a high end mod. Apparently, the manufacturer of the EA, Electric Angel, saw the error in their ways, because eventually they offered a bottom button conversion kit for their old style EA. Long story short, I got one, and I must say that it is one of the nicest bottom buttons in my collection, which includes things like the Nemesis, Paps, Stingray, Ihybrid. The switch is flush with the lock ring, which locks and unlocks with just a slight detented twist, right or left.
I think I recall a big negative with the EA bottom button as well; it is not user serviceable. You can't take it apart, so... if the spring or whatever issue arises it's done for.