Yesterday I got the Razer Deathadder. So these are my thoughts on it.
The Design, to my eye, it's a very nice looking mouse. And it fits my hand perfectly, I've had my hand on this mouse for a few hours or so and I've found it's extremely comfortable to use. The black body and blue lights just looks sick. I wish you could change the colors but that's only on the top model of mice, the Razer Mamba. Oh well.
The sensitivity is amazing. I have it set to max and I like how fast it is and how fast it reacts to the movements. It being a wired mouse there is 0 lag between movement of my hand and movement of the cursor on my screen.
I still haven't set any up, but Macros sound like they could be seriously useful. One of my friends has a macro that opens up and signs him into World of Warcraft. I personally thought that was pretty cool. Now I don't play WoW, but I'm looking into trying to set mine up to open up my blog or sign me into starcraft 2. But for now i have the couple extra buttons set to copy and paste because I'm just cool like that :d.
I would recommend this mouse to anyone. and for under $50 on newegg, it's not to pricey either for such a good mouse :P.
The Razer Deathadder one newegg.com -> http://www.newegg.com/Product/Product.aspx?Item=N82E16826153055