I've been an avid user of gaming gear and peripherals for 10 years now, and have been reviewing mice for the past 5 years. In terms of technology and performance, and also functionality of gaming mice, they've definitely come a long way. From the older inception of Razer "Gaming" mice, older and legendary Microsoft IE3 / IO1.1, to the extremely wide range of companies of SteelSeries, Logitech, Corsair etc. who make mice today, sometimes it's very difficult to determine which mouse is right for you or not. In this way, the same goes for mousepads, keyboards, headsets, and the like.
When people ask me which mouse is better and claim that some mouse is definitely better than another, in the end it really depends. There are of course certain objective things that could be looked in in terms of specifications, the sensor performance, firmware implementation, scroll wheel, switches, lens implementation, chassis shape, and obviously the build quality. My personal view is that performance at the very general level, does not have to be "pitch perfect" as long as the mouse performs without what I call a serious defect, ie. the old z-axis issue, or severe jitter or pixel-skipping. What it comes down to in the end, is whether or not you're comfortable with your mouse and whether you feel like it's helping your gaming. To some extent, like muscle memory, your body has a way of adjusting to the performance of the sensor and the shape of the mouse, and even if you use a new mouse which supposedly has a "better" sensor, you may find yourself not liking it very much.
That aside, I will be posting my own ranking of gaming mice that I've used over the past 10 years. Note that this list only represents how much I like the particular gear, be it mice or mousepads, and not does not represent anyone else's opinion. Please also note that I only put gearthat I've used and tested before, so I cannot speak to mice that I haven't used.
Hopefully, it'll serve as a useful reference for people who may not have had as much exposure to gaming gear as I have. Bottom line, you do have to use as much gear as possible to find what you like the most. To the extent that you are cash-strapped, unfortunately I cannot help you in this regard. In any case, best of luck in the search for your own all-time favorite gaming setup.