I was noodling a little today on my Essence and turned to my Collings City Limits arch top guitar.  Rather than plugging into my usual amp for it's use, a Schertler UNICO ( which I really like because it is so devoid of coloration); I plugged into my PJB Roadcase.  Wow, the tone was sooo warm/fat/thick with the EQ flat.  Loved it!  I don't know yet how it would sound with other acoustic/ electric guitars, but I may experiment some.  I love this amp.

I've got a PJB briefcase combo and have used that many times with my alembic Orion guitar live and mic'd up it sounds great. It's also great with acoustic guitars as well.
 
I know we are at different ends of the PJB scale but they are great products.
 
jazzyvee