Audio Research or Conrad Johnson Phono Pre

I don't really know but C-Js have their own "house sound" so if you like their sound you would like it, I'm guessing. 

I have a c-j TEA1 series III, and before that I had a TEA2MAX.  Both Audio Research and Conrad Johnson make top level kit and are definitely direct competitors.  Over the years both have improved with every new product produced.  Both sound exceptional.  The newest stuff is absolutely neutral, gone are the days of tubey warm, mushy bass etc.  Frankly the TEA1-III into their GAT2 line stage is the best I have ever heard.    C-J has given me exceptional customer service as well and my local dealer is fantastic.  And that is the reason I have an all c-j system today.  Audio Research makes wonderful stuff too. and if you have a good dealer you can't go wrong with them either. 

"...The newest stuff is absolutely neutral, gone are the days of tubey warm, mushy bass etc..."

It's been a while since I owned any C-J gear. Even back a decade as you moved up the line the gear seemed to get more neutral.