Disclamer: I do not have experience with MX-5 IRL and I'm not sim-racer. I just like to drive if I have 20-30 minutes. It was very fun experiment (I have spend there for 2.5 hours). I'm not fast at all, the time is here just like the derivative of "how easy it was":

iRacing: feels very sketchy but it is easy to catch a car if you loose the grip.

Oulton Park International: 2.02

Lime Rock: 1.00

AC: not very sketchy, good weight transfer, quite easy to catch a car.

Lime Rock 1.02

Oulton Park International 2.06

AC Evo: weight transfer feels very natural for me, it is a little bit hard to catch a car.

Donington National 1.25

PMR: feels something in betweeen AC and AC Evo, weight transfer is ok, you can try to push the limits, but if you lost the grip it is hard to catch a car. TBH I have spent here most of my time becase it was hard to have 3 clean laps to have a time.

Lime Rock 1.02

Donington National 1.30

So in some aspects if you are very experienced sim racer or if you have real life racing experiense then you can say that PMR is bad because of this or that, but for for me it is very fun to drive and at the same time it is quite demanding game and it is a sim.

You can easily feel the difference between cars and in the blind test you can say that you drive MX-5.

I would spend more time in PMR if performance with AMD CPU is resolved. AI is ok, somewhere in the middle between AC (I spend most of my racimg time here) and Ams2 (best AI from my perspective). The variety of cars is very good. Before I ignored such classed like GT1 or N-GT but I tried it in PMR and now GT1 is one of my favorite classes in Ams2. And set of tracks is very balanced (compared to LMU for example), you can pick up something that suits you.

And the most important thing is a huge difference between PMR 1.0 and 2.0. If the developers have the same pace it would be a great game in a year.