I finally got a chance to try the Preferred Shuguang 274B that I ordered from The Tube Store, and compare them to the Philips 5R4GYS I obtained from Upscale Audio.
I tried each in my recently returned Ultra, and in my front side Torii. It's a bit of a toss-up in the Ultra, where I perceive the soundstage to be a bit wider, and the background blacker, but in the Torii, the Philips exhibits better and tighter mid-bass and bass control. On double bass, the difference is not subtle. For half the price, though, the Shuguang 274B is a bargain.
I have not yet tried the ValveArt 274B from Cryoset, but I am going to. As I understand it, it is the
same maker/make as the Shuguang. Getting it cryo'ed from Cryoset even cheaper is just sweet.