I like the stainless steel construction as well as the revised design. Price is (Cough cough) a little steep IMHO but nature of the beast catering to small batch manufacturing.
I personally would NOT opt for the little willy version like early Triumphs had because its pretty obvious they can have challenges long term with leakage with a moving willy going in and out like that with fluctuations of pressure.
Only a plus if you have phallic exhibition tendencies.
However its is worth noting Triumph stopped using that design for similar reasons.
Better choice is a liquid filled Oil pressure gauge mounted in your choice of location. You can source vintage style gauge faces if you like. I personally believe fitting a gauge makes you a better rider, owner and caretaker of a vintage bike. (Dont flog the beast with cold oil!)
I also often make my own LED idiot lights for pressure warnings.
Despite the improved design, even Triumph had issues with ther PRV and circa 66-67 there was a factory service bulletin for testing the PRV and what to watch out for. But cleaning and service usually does the trick. Norton INOA tech guide has also suggestions for the Norton versions and there is a procedure for testing and spring pressure. I still have 3-4 new replacement springs in inventory for Nortons and every rebuild gets a good servicing of the PRV,,
They tend to be an item nobody looks at or thinks about until there is a problem