I don't own a 642 at the moment but that or a 442 are two revolvers I have favorable opinions of and will probably acquire one in the next year or so. I used to have a Model 37, which I traded for a 640, which is significantly enough heavier in the pocket. I wish I'd acquired one several years ago when they were cheaper, but other things kept getting in the way, like having to have a Shield or Glock 43 (currently a Sig 365 is on the list ahead of the revolver), or new rifle....
The are only two real cons for carrying a 642: 1) you're parachuting into a hot drop zone to be immediately overwhelmed and that's the best you have, or 2) you carry it without training with it and understanding its strong points and shortcomings.
Recoil is not pleasant with anything more potent than wad cutters and since velocity seems to be a key ingredient to making hollow points perform consistently from a two inch barrel. I found on J-frames, the best grip for me in terms of concealment and recoil mitigation are the Bantams by Hogue. They aren't perfect, but they also don't add a lot of bulk to the gun making it harder to conceal and don't cost an arm and a leg to find out you don't shoot well with them. That said, Hogue makes quality products. I like them better than Uncle Mikes or any of the wood boot grips available. I am generally a proponent of leaving the action and trigger pull of a gun alone - the grit will usually smooth itself out to a degree through dry and live fire, but having a shop round the face of the trigger, edge to edge may make the trigger press pinch the finger less. And some orange paint or nail polish is probably going to be necessary to make the front sight stand out. Still, the airweight Centennial is one of the best all round concealed carry guns out there.