I think the stock 637 trigger is the same as any other jframe, perfect in every way
Seriously, S&W teaming up with the gun smoke family is almost as bad as the whole lock debacle. If you must have a slicked up action out of the box, Look for a 637 PC. The last thing you want is the name of some terrible TV show etched into your revolver.
FWIW,
I've had two 637's in the last two years. The first one had a cracked frame and the second one a broken stud. Neither gun could be repaired and had to be replaced. The second gun broke this summer and I'm still waiting on it to be replaced with a 638. S&W gave me the choice of any j-frame model in place of the 637 or any gun from their catalog, with me owing the difference.
The customer service rep at S&W told me that the 637's come back far more than the 642 or 638. He did not have a reason and I would have elected to have it replaced with a 638 regardless. I probably have bad luck but I thought I would just mention it. Otherwise, I loved carrying and shooting the 637.