Until recently, I had been using an old boss guitar compressor. So I decided it was time to upgrade this essential part of my effects chain. After a lot of online research and listening to different compressors, I had narrowed my choices down to two: This Keeley bassist compressor and the MXR M87 compressor.
Although both compressors sound very good, with little to no noise and/or tone colouring, the Keeley won it for me. This is due to a couple of (personal) factors.
The M87 does sound great, and has just as little noise or tone colouring as the Keeley (virtually none), but also sounds more subtle. As I'm not a subtle player (or guy) myself, and also because the multitude of options the M87 offers (6 knobs instead of 3 on the Keeley) I finally decided on the latter.
Lastly I would like to add that compared to the M87, the Keeley felt a bit more sturdy, which makes me feel confident using it in live settings. The M87 on the other hand would win in the studio, as it has a bit more possibilities to really finetune the sound and extent of compression.