After using my NOS GEC U52 with my Shuguang Natural sound 2A3 for around 100 hours, I have to say I still prefer the EML 5U4G. Although the U52 produces a clearer, more detailed sound and bigger soundstage, the EML is more full sounding and sounds more realistic to my ears. The bass with the EML is also more impactful.
Good to know. I just received a pair of Psvane WR2A3 tubes and, to my ears, they do not sound as wet as the Psvane Treasure MkIIs I had (which I may incorrectly assume sounds much like the Shuguang Natural Sound). The U52 seems to be a good match for the WR2A3s though they need some burn-in. I am curious about the EML 5U4G though (just a matter of $).