Some time ago, Hangsen "Coffee", but only the VG version was my ADV. For some reason, this is super rare, and the PG version never tastes that great. Then Hangsen "Chocolate Caramel" tasted like the best ever and was my ADV, but for some reason I am over it now. Hangsen RY4 is ok as well, as far as I remember
I did LOTS of DIY experiments too, and most of them didn't turn out well.
EXCEPT that now 12% TFA DRY4 is my ADV, with some drops of pyrazine. It has just the right mix of caramel/tobacco IMHO. Sometimes I spice it up with "Cool Mint" or similar to give it a refreshing note.
Wife likes fruity flavours (me SOMETIMES too) and the Atmos Labs Blue Raspberry is actually amazing.
I also once tried almost the entire range of Halo menthol types, and I found them weird and overrated.
Re: Dekang...I remember getting me the Dekang RY4 not too long ago and at first found it awful (like a stale ashtray) but all of a sudden I liked it.