Thoughts on phono stages; Audio Research PH 9 vs. the Ref 3?

The ARC Ref phono preamps are terrific. I'm still using my Ref2SE Phono with my Ref6SE and it sounds fantastic. If you're interested in the Ref3 Phono, you might want to wait just a little bit. With ARC replacing the Ref6SE with the new Ref7, it's likely they'll also eventually update the Ref Phono, too. That means there will be dealer demos offered on the Ref3, and those come with warranty and a steep discount.

Also have the REF. 2SE and think it’s fantastic, 

The "Low Gain" / MM mode (6H30 stages) was absolutely stellar; still probably the best I’ve heard / owned. The "High Gain" mode was indeed very good sounding, but not without issues and probably not quite in line with this (very high) price point. Feels like some noise shielding and grounding optimization was missed. I fixed that by using Low Gain with a SUT.