I am curious what the attack/release characteristics are, and what the overall sound is like, could it be compared to anything else out there.
The attack and release times are difficult to characterize, since they are dependent on the amplitude and duration of the input signal. The timing circuit has two modes, slow and fast. Basically, it tries the slow time constant first and switches to the fast time constant if the signal is large and persistent. A big input signal, say 15dB over threshold, will get squashed very quickly with an effective Tc of about 5mS, while a 5dB step takes about 85mS for the same relative amount of gain reduction. Effective release times vary greatly, from about 2x the attack time for small, slow signals to about 20x the attack time for large, fast signals.
As you might suspect from the distortion and frequency response specs, the overall sound is clean. A comparable unit would be something like a later dbx 160, like a 160X, or 160A. The B16 has lower noise and distortion than either, however, because of the short signal path and high quality ICs.