Phil,
I like the Soro SE Phono much better than the Oto. I use Tungsol 5881 (4), Ken Rad VT229 (2), Tesla ECC803 gold pins (4), Bugle Boy 6dj8 (1), And 2 12au7's, but I can't remember what I have in it now.
The phono stage is excellent for MM cartridges. Before I got my Supratek Syrah, I used both a K&K stepup, and a Tom Evans Microgroove to match it to my Denon 103r. The Tesla's really made a difference in the phono stage. For the money, I think it is the best integrated with phono out there.
I paid a grand for a later one owner unit. I considered it a steal, but they seem to be going for about $1200, or a little less. I do feel it is worth the 4k new price tag!
The only way mine will go is if a higher level AN product replaces it. Now that I have the Syrah, I want to go AN monos one day. I should have bought Carl's Conquest when he had it for sale.
If you want to greatly improve the Soro's sound, get some AN speakers and cables. I have the AZ3's, and they sound much better with the Soro than a 4k pair I also have. Could be one of the best $1500 speakers out there. Also, the AN Lexus speaker cables give quite a bang for the buck.
Joe