Can't speak for the Washburns specifically, I play an SS Stewart that is likely a Regal built instrument, very similar to the Martin- bent top, same size, well built, 13" scale oval hole. Mine is all koa and a very nice player. Short sustain, not as loud as a long scale carved top instrument, but It can be heard across the room in a jam- at least by the guy straight across.
How much you like them will depend on your expectations- and maybe what you pay to get one. A nice old bent top might go for $200, a Martin $400+. They are not so sought after as to be pricey and you get a lot of instrument for the money- fine wood, excellent build quality, for a reasonable price.
A lot of them have high action- or a low bridge- as the necks raise up some over the years. It is usually not worth repairing them. If you are buying from ebay look closely at the height of the bridge, ask about the action and look at photos to see if seems playable, also look at reflections in the top, looking for a wave around the neck and sound hole area indicating that the top is dipping down and the neck is raising up. They all have a bit of that. Bridge height and action are the key indicators of condition- not to leave out obvious stuff like seam separations etc.
Be yourself, everyone else is taken.
Favorite Mandolin of the week: 2013 Collings MF Gloss top.