Like you I'm also considering upgrading my phono stage.
Which one to buy is almost a hit and miss depending on who you talk to and trust with these advises. Bottom line it will be your ears that will decide (sorry to say)later after you get the piece on your system. BUT there are a lot of reviews from inmates and reputable audio enthusiast reviewers that might help you decide.
Questions: 1) What is your budget? 2) would you buy a built unit or kit? 3)Would it be a tube, Solid state or Hybrid design? 4)Will use MC or MM?
I have built the AES/Cary Ph-1 5 years ago and still use it to this day. After several happy years with it I have come to the point that I needed to upgrade to MC: 1) more gain and 2) A more quiet phono stage. 3) solid proven design. 4)Priced competetively w/out breaking the bank.
From my readings on these, the Hagerman Cornet2 is worth considering. A lot of happy owners about this unit: fun to build, good sonics, quiet, will not break the bank.
The Tercel seem to be another contender but not attracted by their "no return/no audition" policy.
Decware ZP3 is another reputable vendor in the field but I hesitate as it has not been around long enough IMO. Nor have I read enough reviews about it to help me decide. Very attractive piece I have to say on the ZP3!
The bottlehead is also a good contender but I feel it will be another AES PH-1 with different type of tubes.
Reading about the "Art Audio vinyl one" and "Art Audio Vinyl reference" phono stage reviews from Audio gurus & from lots of happy inmate feedbacks(designed by Kevin Carter of K & K Audio)I'm convinced that transformer coupling approach is the way to go. I look forward to building mine soon! Why? IMO It's a solid proven design, quiet, MC/MM capability, gain selectable, competetively priced and surely fun to build & comes with a handsome faceplate/enclosure. They come in 2 flavors (basic & MAxx-out kits). NO I'm not affiliated with any of the vendors mentioned here.
Hope this helps. Good luck with your decision making..and most of all enjoy! Joel