@iamoldschool, I am a recent convert to pedals. I played for years with no effects. I now have a Pedaltrain Nano+ board with an Eventide Powermax supply, which I got at a good price but is serious overkill for the Nano+, with which I am running no more than 4 pedals at a time. But - No batteries!
I really like the Keeley Bassist just from my initial playing with it today. I auditioned it with my both of my Ibanez Artcores, and the Keeley made both of them sound fabulous, getting rid of the funky ups and downs of those basses throughout their registers. Most people on TB say the Keeley Bassist is very neutral. I would say it made both of those two Artcores sound the way they should sound, so it actually added a lot to their sound.
I will be playing some of my other basses through it in the next few weeks and see, but boy, I really like the Keeley Bassist so far, of the three compression pedals I own. -- MV