OP: Note that the Keeley is quite literally a DBX160 in stompbox format. It uses the same VCA chip and everything. (I know the 166xl has many more features, but I believe the compression is similar tonally)
That being said, and to help provide another datapoint towards the original question,
@Johnny Crab which setup do you prefer?
Are you saying the Keeley is a dbx160 or a dbx166 in stompbox format? The 160/166 are VERY different quality units.
The dbx160. now often referred to as the dbx160VU to avoid confusing it with the later and less desirable dbx 160X/XT/A, was a classic compressor. Really good if you like the characteristic and rather "hard" way it can clamp down on your signal, and if you can live without adjustments for attack/release. It's not my personal favorite style of compression, but at least the 160 does it really well. I think I could probably enjoy having a "dbx160 in a box" on my pedalboard, when used at moderate settings.
The dbx166 is something I wouldn't let near my bass signal path or my studio. I guess the 166 can be decent as a budget option for less important channels in a PA system, like toms or something... But I definitely wouldn't want a "dbx166 in a box" (minus the attack/release controls) on my pedalboard.
Btw, is there a concensus on whether the Keeley Bassist or GC-2 is the best option for bass? I definitely don't want a compressor that "overshoots" on low notes. Does that mean the GC-2 would most likely be the better choice for me?
The thing is, I'm looking for a reasonably priced "one knob" compressor for my pedalboard. I'm sick of repairing my EBS Multidrive and can't trust it anymore (have they improved the build quality of these by now?). The MXR M87 is great, but too fiddly on a dark stage. The Markbass Compressore is also great, but too dark/colored to be my allround "always on" compressor.
This Keeley Bassist (or GC-2) seems like it could be an interesting option, but not if it's a "166 in a box". I like some of dbx's higher end gear, but their lower end comps (166/266) make the Behringer Composer seem like a boutique compressor by comparison.