Not exactly sure what it takes to impress you. The ac40/50's construction is unique in the bass world,which certainly made an impression on me. (Try finding another semi hollow neck through-if one exists,it probably is a custom design costing 5 times more) The main thing is the quality is way above the price.
But,as far as playing it unamped,it has pretty much zilch acoustic volume. I pick mine up and play it unaccompanied and unamped,and can hear it just fine,but an amp would be necessary to play along with anyone,even in acoustic settings. However,i found that to be true even with the huge thick bodied Tacoma Thunderchief i used to own.