I assembled my own guitar pedal last week. I purchased two pedal kits from Build Your Own Clone (BYOC) a couple years ago, not thinking it would take this long to start them. I bought the Optical Compressor and Overdrive 2. Respectively, these are among the easiest and hardest builds available. Since I've done nothing like this before, I naturally began with the compressor.
I've never owned a compressor, and I've only played through one a few times. I know the effect is to limit the dynamic range of my playing, and I've often found myself wishing I had one in my signal chain. It would be nice to have a little studio squeeze in my own rig.
The whole project only took me four or five hours, pretty good for my first build I think. Plus I haven't soldered anything in four years, and even back then I was only a beginner. The documentation provided on the site is pretty extensive. Some bits were confusing, but the incredibly active BYOC community forum has answered all common concerns many times over.
When I finished, it worked. That was unexpected.
I tried the pedal (powered by my Pedal Juice) on my Roland Cube 60 practice amp with a few different settings and guitars. Controls are simple: a volume knob and a sustain knob. They mean it when they say "can't tell when it's on but miss it when it's gone" on the product page. I could only really hear the effect when turning the knobs to the extremes. With the sustain set high, I could strum a chord and hear it forever. Otherwise it was difficult to detect a difference when the pedal was on or off. I definitely felt better after playing with it for a while. Maybe it's just a fancy Dumbo feather, but it gave my fingers some extra confidence. Really looking forward to testing this out at high volumes (i.e. next Dazed and Confused gig).
Next step, Overdrive 2!