There's no way to answer that question, you need to know the exact torque, speed, and precision requirements for your application before you can chose a proper servo. If this is for general use pretty much any servo will do, though metal gear ones are good for robotic work because they handle torque better.
Based on their specs those servos are so close in performance as to not matter. If you're looking for something of higher quality find servos that have more than 3 poles, the more poles the motor has the smoother the motion will be, but the more expensive the servo will be as well.
Deadband is pretty simple, the larger the deadband is the more 'slop' there is in how firmly the servo will hold it's set position. I have no idea why that one has a spec for 2ms deadband it makes no sense, deadband is almost never listed for standard servo's.