The button was no longer "clicky" hence my ordering this kit.
Overall, the guide was pretty straightforward, but getting the earpiece speaker to stay in place and the logic board to seat properly in the case during reassembly were the two most time-consuming steps.
It was quite the feeling of relief and empowerment when I hit the power button to start up the iPhone and everything worked after reassembly.
The guide needs to include a pointer about the small rubber bumper on the edge of the logic board (protector for display cables) as mine came loose before I could see where it came from. It is mentioned in the comments but should be in the main guide.
Also, the #00 screwdriver did not have a narrow enough tip to fit the screws so I had to find an eyeglass screwdriver.
Phillips #00 Screwdriver
Flathead 3/32" or 2.5 mm Screwdriver
P2 Pentalobe Screwdriver iPhone
iPhone 4 (CDMA/Verizon) Power and Sensor Cable