I have WN Winsor Red which I think is the best kept secret in oil paints, cheap, wonderful red that simply gets it done.

I have W&N’s Scarlet Lake, which is in the same ballpark (Scarlet Lake is more scarlet, Winsor Red is a more mid-red blend). But my painting style doesn’t really need it; I only have it “just in case” I need to go there, because I have no other high-croma red.

But regarding the OP: Whether or not to use high-chroma colors, is a matter of the painter’s subject-matter and painting style. Also a matter of medium (oil, acrylic, watercolor?). Landscape artists, especially in oils, usually don’t need much by way of high-chroma colors. Nothing in nature is an intense red, except for some flowers, and that’s a genre in itself. Portrait artists might prefer to use a duller red, as it can more easily be used to modify skin tones, without excessive color shifts. On the other hand, modern abstract artists often use high-chroma colors.

There is also the issue of mixing performance with other colors. Some pigments “play nicely” with other commonly-used colors, producing useful mixtures that can be easily controlled. Others don’t. Using mixtures to get color gradients is common in landscapes and portraits, but may not be very useful in modern abstracts.

Single pigment Pyrrole red PR 254 is a very good choice of red for a limited pallete of high chroma primary. Considered a mid red, not leaning to blue or yellow, high tinting strength. Pyrrole scarlet, PR 255, also strong bright red, leans a little more yellow than PR 255. Can be more or less opaque depending on Mfg.
I got some PR 254 Pyrrole Red, M Graham. Very good!

My W&N pyrrole red is brighter, cheaper, and more consistent in mixtures than my cadmium red, haven’t used my cadmium red since.

Regarding opacity, pyrrole red has about the opacity as cadmium red, there is a very slight difference, but it’s so minor that it doesn’t bother me at all. It’s not like the difference between azo yellow and cadmium yellow.

If you really need the super highest possible opacity, cadmium red is still the most opaque by a small margin, but otherwise pyrrole red is superior in every way.

Pyrrole Red shifts slightly towards purple in tints (although not as much as Naphthols and Quinacridones), while Cadmium Red has an insignificant hue shift

Brands using PR254 on its own shift to pink when adding white, but mixtures of both pyrrole do not.

This partly explains why W&N winsor red seems to be the most popular pyrrole I think. Winsor red doesn’t have that hue shift you mention.

W&N has PR254+PR255 in a single tube. PR254 does have the shift to pink if you add white, but Winsor red does not, due to the addition of PR255 which keeps it out of the pink range.

PR254+PR255 is superior to PR254 in my opinion.

I’ve found cadmium reds to be more opaque than the Rembrandt Pyrrole Red I tried. As the W&N red is cheap I would have thought it would be about the same level of opacity as the Rembrandt version?

I haven’t found Rembrandts to be that much more oily when compared to W&N paints?

I think some pigments are more transparent compared to the equivalent in W&N (PBr24), while others seem the same or more opaque than the W&N version (Titanium White).

That’s not to say that they both aren’t oily paints. They’re both oily compared to something like Old Holland. But yah, Rembrandt and Sennelier are probably the oiliest paints out there. W&N is middle of the road in terms of oilyness I would say.