Progressive render is fine for finals, except in interactive model. I was missing the interactive variable.
It also seems progressive as a final render works a little better. I just rendered an interior that was taking a long time to clean up in interactive mode, cleaned up a lot faster in final mode.
Mind that in IPR (talking about the regular CPU IPR), LC settings are overridden from the set ones with some lighter values for better interactivity. This indeed could lead to slower cleaning of the noise if you directly compare it to production progressive.
But as you all already got it - IPR button for tweaking the scene, Render button for the final image (no matter bucket or progressive).
BTW we’ve improved how the VRayDenoiser’s “Update” button works in IPR. Now you can leave “Post effects rate” to 0 and force an update manually while rendering - it will create an “effectsResult” channel and display the denoised image there.