I've owned both Cary and Golden Tube, the SE-40 as well as 300b model. I currently own Cary 280 v12 and SEI 300b. I always liked the Golden Tube amps, fortunately I never had problems before I sold them in favor of Cary. Personally, I like the Cary much, much better; but remember I had stock Golden Tube, no upgrade from Soniccraft which does great upgrades to the Golden Tube. I believe they are located in Arkansas.
If you decide to go with Golden Tube you must get the upgrade and better to get the SE-40. The upgrade package is slightly less than $300plus labor. Soniccraft also has an even better package for around $500.