I have several eGos, Eastmall Rivas, Hello Rivas, and T-Rexs. Performance wise they are all almost exactly the same. I like the T-Rex the most though. The button is metal and has the best feel out of them to me. I also like the LED lighting up in a ring around it. The eGo and T-Rex both are inset more around the button, so the clip on button protector fits them well, whereas on the Rivas it can slide off easily. My current favorite is my new Stainless steel T-rex, I love how it looks and feels. Just saw the new Steel Riva SE though, so will probably order one sometime soon also.