Single chainring setup..
Switching to the Raceface requires a new 30mm bottom bracket..but cost aside which is the better crank?
Are the RF narrow wide chainrings any better than the shimano offering?
Pros and cons of each?

In terms of quality I don’t think you can get anything better than a shimano crank.

But you can get lighter (carbon from RF or Sram).

The biggest plus for me with the RF is the cinch system which is excellent and means you can run rings smaller than 30 (round) or 32 (oval) and it looks a lot neater. That is only really an issue if you are running cassettes up to 42T though for me as the 46T shimano negates the need for a ring under 32T but it is heavier.

Oh and you can get Aeffect one which are 24mm axle for normal HTII style BBs but they might be a bit heavier and less stiff (if you can tell the difference).

Why don’t you go for RaceFace Aeffect, normal 24mm BB and the awesome clinch system.

I like the idea of getting a green Atlas crank, that will match the colour of my frame.
Although there’s not a lot of difference the aeffect isn’t on my list..

I was looking at this, I wanted the ability to run a 30t oval. Both the new shimano and cinch let you do that. I didn’t buy one in the end but while I wanted the raceface it was hard to justify- looks neater but it’s the same weight at best and considerably more expensive.