If you want something similar to what you're using at the moment, have a look at DM1 pro S or the nixeus revel which have approximately the same shape as the sensei raw (basically clones). I'm currently using the DM1 pro S and I'm very happy with it. They only have sidebuttons on the left side as well for right handed persons. The only drawback about the mouse is that they don't have any dedicated software at all, so you're locked to using the presets (i've always been using the 800 dpi step so I don't mind not having any kind of software), and the DM1 pro S got a braided cable that can be a bit too stiff compared to the rubberized cable from the nixeus revel (however I've been using a mouse bungee with the DM1 pro S and have no problems with cable tugging). Both mouses uses the optical PMW3360 sensor which is one of the best in the market at the moment, so the performance will be considerably better than your current sensei raw which uses a laser sensor.