If you're interested with the Deathadder, see if Best Buy has one on display or in a packaging where you can feel the ergonomic shape of it. If it's comfortable to you, just go for it. It's got good quality parts and it's the best thing razer makes.
used a lot of mice in my time. some of the best feeling 1s are the razer ambidextrous mice like the Lachesis but they have poor build quality. the g400 is a better mouse than the g500 as the side buttons are easier to use without pressing another that you didnt mean to. it also has an improved sensor. i saw 1 advertised for 25 the other day which is unbelievable value for what it is. roccat kone+ and the kova + are 2 good mice also... the corsair vengeance mice are good but a little outside your budget.