BYOC Optical Comp: "BYOC" stands for "build your own clone"; they make kits and project plans for you to build your own copies of popular pedal designs. This one is their optical comp, and I built it from their kit using only the parts and plans included in the kit.
First I should mention it was an easy build. All the parts were present, the instructions were clear and well-illustrated, the circuitboard was marked clearly, and there was no pesky transistor biasing or other complicated processes. The only minor glitch was the instructions don't specify the +/- orientation of the LED light, but it wasn't hard to figure out. I was quite pleased with the kit overall.
The resulting product is also quite decent. The kit includes a couple larger caps for better bass handling, and it does a good job at that--it doesn't lose any low end, though under heavy compression the lows can seem to roll off at they get squished harder. The highs are good too, maybe not crystal-bright, but good. The noise level is fairly low, about the same as many other "boutique" comp pedals (not silent, but not bad).
The attack is fast and the release is quite slow. This works well if you play fairly steadily, it handles your signal in a smooth, flowing way. If you play with wide dynamics or long rests however, the compression envelope can get a bit weird, as each note triggers different amounts of squeeze starting from different points in the release of the previous note. It's not necessarily a bad thing, just something to be aware of. In this way it's not as consistently smooth as the Demeter for example, and has more in common with the LA3A or other "quirky" vintage comps. I'm not 100% sure, but it seems like the sustain knob controls the gain of your signal into a fixed threshold. This makes it suitable for a wide range of instrument output levels, but it also means that heavy sustain settings can sound very squashy and effected. It's more "invisible" at the lighter sustain settings. At stronger settings it can handle some peak limiting, but it's not a brick wall for extreme spikes.
Comparing to other optical comps: At lower sustain settings it is serious competition for the Demeter; at higher compression however, the Demeter is much smoother and less effect-y. Compared to the BBE, the BYOC has a wider range of squash available, but the BBE can be found for a slightly lower price, fully assembled. I won't say the BYOC "kills" any of the competition, but it is a great product and value for the money if you build it yourself.
The parts used in this kit are the same as the ones in expensive boutique pedals, and if you build it properly, then it is a good rugged pedal. It's not visually attractive by itself, but you can decorate it however you want. It runs on standard Boss-type 9 VDC (or up to 18 V if you want, for more headrooom), and the included footswitch is true bypass.
Price in USD: new $75, used price depends on how well it was assembled and painted, but it should be less than $50.