I have the Jolida 502B, a Cayin A-88T, and a McIntosh 275 Gordon Gow edition. All of these units are stock, out of the box, and have equal hours on them. I've been switching them around on different speakers. Klipshorns, Klipsch LaScalas, JBL Jubals/L-65s and JBL 4315s. The Cayin is the most open, sweet in the mid and high range with good bass. The Jolida 502B has better tighter bass and is not as sweet in the mid/high range but very open. The Mc 275 has good bass, as well, but is not as open or as sweet as either Jolida or Cayin. I've read some of the reviews reguarding Jolida's build quality. From my experience, 45 years of audio, I'd say they are all very good. I like the Cayin's looks and build quality the best followed by the McIntosh and Jolida which seem equal. I have used the units in listening trials against my McIntosh 7300,7200,2205, and a 2105 and now prefer the sound of these, tube units, to the S/S McIntosh units.
I'd like to add that tube preamplifiers and tube amplifiers are the way to go on horn loaded speakers. These new units are far above the Dynkits, Eicos, and Heathkits I built and used on horns in the 50s and 60s.