The video excerpt below is from Erin Kennedy's February 2015 Robot Party, where I discuss the reliability of the finger actuators. The Robot Party is an online community of robot makers who share their projects and discuss robotics ideas.
Materials
As mentioned in the design section, several different materials for the fingers were tried. The ribbed hose selected for the prototype worked the best. However, it is far from perfect. The fingers do fail after repeated use. Others are encouraged to investigate other materials and techniques.
Reliability
Sometimes the tip of the finger blows out, as shown in the picture below, or it fails along the length. These failures are caused when the plastic fatigues and one of the cuts in the finger splits beyond the stress relief holes.
Potential Modifications
A 3D printed design to replace the ribbed hose is an interesting option. The growth of 3D printing has made a custom designed actuator a reasonable possibility for a hobbyist. The ability to manipulate design parameters and rapidly prototype for increased reliability is very attractive.
This project will be updated if a workable solution using 3D printing can be developed.