Just remember that you can only use 5 pneumatic actuator, so you might want to save up two actuator by using a servo instead...
Pneumatics can be really useful at other bigger size components, especially with the 2" bore actuator that can push 180 lbs of force (and a little less pulling). Really good for lifting goals a little bit to transfer weight onto your robot.
Servo is a really weak motor, so don't expect them doing much other than shifting gears for drill transmission, or unlocking devices. When using them, make sure you design it mechanically such that your device doesn't require much force from motor to hold on resulting position...
Take the the technokat's shifter for example. You can design it such that when the drill is in low gear, the servo "plus" attachment is perpendicular to the shifting metal strip. So, if it try to push back, it's pushing against the servo's shaft instead of spinning the "plus" backward... This kind of thing.
But it is a really simple motor to use, if you do it right. Doesn't take as much power as the pneumatics if you are using the electric pump.