I think in buying a mouse, you would first need to identify what features you want, i.e. the sensor, buttons, speed, etc. After that, you see what are the options you have then you test it out yourself. Basically you want something that is comfortable for you to hold.
Buying a mouse is just like buying a condom. There are so many types, shapes and flavors. I might recommend you something I like but it might not fit you well. Therefore, it's best to try it out and decide yourself Personally, I would say go for the Steelseries mouse. Razer stuffs looks sexy but they are filmsy and bad in quality.

Actually I did not buy condoms but just using it as an analogy Some shops in Low Yat have the mouse displayed so you can test them out. I used to own Razer DeathAdder when it first came out and it was a good mouse until I tried Steelseries stuffs like Ikari Laser, Sensei, etc. Like I said, it can be individual preferences.