I've had mine for about 2.5 weeks with I'd guess about 30 hours on it.  I think the overdrive sounds are fantastic... i boxed up my Zendrive the first night.  A couple thoughts...  run the overdrive (red) with the preamp boost (green) on as well.  I have found that to be plenty beefy.  Play around with the Ratio and Level controls to find more of what you're looking for. (I haven't touched it yet but there's an OD trim knob oon the back panel to adjust as well.)  I'm running through an Eminence Neodymium that has been reconed with a Tone Tubby hempcone...  sounds fine... I think your C rex would be in the same ballpark.  I also have an EV 12L, but that's a bit bright for me right now... at least in the small room where I play. 

There are so many variables and knobs to tweak... it takes time and experimentation... but I'm loving the sounds I'm getting.  I have been playing a tele through it most of the time... but my lap steel with humbuckers sounds fantastic as well.  I've heard that it takes about 60 hours of playing time for the amp to get "burned in" so hang in there.  Hope you find the sounds you're looking for!