Just took King Edward II on a spin up WCML North to see how fast/powerful it is, with a rake of 12x RW3 default Mk2 carriages. I have lots observations! Please take my following comments as simply observations, not criticism.
1. Edward I and II have different chimneys - the former seems to have the double kychlap. Are the game physics between these two trains still the same (not that it really matters, but just curious).
2. Both train whistles are barely audible.
3. Brake application and release rates are really high - same goes for the Ivatt!
4. I see that you have a different design philosophy to Kuju (MSTS) and RSC, with the use of an obvious cap in steam generation rate (same goes for the Ivatt).
5. Steam usage rate/reverser relationship changes greatly when accelerating past 40mph, resulting in me adding forward reverser to balance usage/production.
6. Steam sounds gets invaded by a "claketty-clack" noise past 60mph. I do not know if this is intentional.
7. Engine seems to have a ton of power at low speed, but hampered by wheelslip. Yet to test this on the 1:40 gradient at Cajun Pass.
8. At above 40mph, the RSC Tornado has far more power.
9. I have not looked at the simulation files. The engine gets to 80mph with ease, but needs some downhill help to achieve a stable speed of approx 90mph max.
10. I drove from Carlisle, 100% throttle most of the way (save for speed limits), making short stops at Lockerbie, Carstairs and Motherwell. My tender ran dry and I parked the train at a siding just outside Motherwell with 0.5 water remaining. The water lasted 90 miles. Any sensible preservationist would refill at Carstairs!
11. A pity about the lack of a proper cab - but I don't spend much time in cab view anyway! The lack of AWS is very welcome!
12. The pack seems to have come with A TON of extra assets! Mk1 and Mk2 carriages of different colours and lots of freight cars. They seem to come with the FP prefix. Thanks for all that - I hope to finally hook up the Tornado with non-glitching Mk1 carriages!
Edit: 13. How on earth did I forget that the sounds below 50mph is absolutely jaw-dropping!

I have no idea how a real King sounds like but the sounds in this packinge is very convincing and immersive.
All in all, this train is a looker! She is also a great joy to drive and I thoroughly enjoyed putting her through the paces.