My home button wasn't very responsive to clicks and became mushy after a year of ownership. It would take a few extra clicks to get it to register.
I have plenty of expeience disassembling and repairing laptops and I was excited to disassemble my first iPhone 4. The repair went very smooth, the guide helped me every step of the way keeping me from damaging any of the delicate parts. Although it ended up probably not needing a new button because I found a large amount of dust and lint had collect underneath it keeping it from depressing. I replaced it with the new one anyway, reassembled it and it worked perfectly.
I thought I had a good electronics screwdriver, but mine still didn't have a long enough shank to get at some of the screws at the correct angle. I ended up having to remove the bit and turn it by hand without the handle. I'd recommend having a phillips screwdriver with a shank at least 4" long and as thin as possible.