I have two 357 Magnum SP101s, one of which has a superb D-A trigger, one not so much. The superb one is better than a first model S&W Model 66 (had stainless steel rear sight) and a Model 29 of the 1970s. My now-given away Model 640-1 trigger action was not even close.

Both trigger actions are smooth with no unintentional hitches.

With the good trigger I can control the D-A action, being able to have/create a near single action ignition because it seems to have a sort've "sweet spot" where trigger can be halted with almost no additional pressure to complete trigger pull.

The good D-A trigger action is essentially as effortless as my LCR - and that's pretty doggone easy.
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What I notice as being different between the good revolver and not-so-good is that hammer has significantly more play. It can even be moved slightly, hammer down, that hammer nose rests in a different spot.

I strongly suspect the not-so-good trigger action will improve significantly with a trigger job to shim hammer's play and reducing rough spots along moving metal-to-metal contacts and connecting joints.

I also suspect that it is extremely unlikely the finished D-A trigger action improvement will match the good one.

Hope this helps.