Never tried one, but the Aguilar Octamizer sounds good to me on demos that I've heard. You can turn down the synthiness too!
Compressor-wise, I love the Origin Effects units. I have full-size Cali76 (great for recording bass) and the SlideRig Compact (fantastic on guitar), and they now do a Cali76 Compact Bass pedal (again I have yet to try this).