Revolver fan speaking out...
I love revolvers, and have a small collection of various makes and models- mostly Smith & Wesson. I own a 642 NRA edition with factory ported barrel that is one of my favorite CC/BU weapons.
That said, for carrying/personal defense away from the home, I would suggest keeping what you have. As others have suggested, having interchangeable mags is a great advantage, and you don't have to worry about adjusting to a different weapon if needed.
If you decided to try to trade your 19, I would lean towards a +cash deal. Being in the market for a used Glock, I can say that in my area, a used Gen 3 17/19/26 is running around $525, $625 w/ night sights; Gen 4s are about $100above that.
From everything I have heard, I would try to avoid a Charter or Rossi, just because there have been too many issues. Taurus is getting better, but still hit or miss on a used one. Older Smiths or Rugers are golden, with Security Six's still asking a premium and early model Smiths under $600 are like finding hen's teeth.