Having owned 3-4 U.S. Stingrays, 2 U.S. Subs and a Sterling Ray34 I am now the proud owner of the Sterling Sub 4, have been for a while The preamp sucks and is hot in the latter but the playability, of mine at least (Thomann), is one of the best of played...I much prefer the Sub Ray 4 over the ugly, sticky, slab bodied US Sub. However the sound of the U.S. Sub is much better because of the better preamp and of course mostly similar to the more expensive USA Stingrays.
So...I put a USA original music man pre amp & pick up in my Sterling Sub 4 and voilà a U.S. Music man Stingray Sound in a bass with the better playability and a lovely jazz width neck. Cost about the same as a U.S. Sub with preamp but I wouldn't change mine, not even for a Ray34