I really approve of the idea that there's no set XP for a particular monster modified by the ECL of the party. No weird rules for combining creatures where multiples of the same creature are CR + additional monsters of that type.
No things are intuitive and straightforward. It feels like the difference between working with THAC0 and modern AC. Like we've finally worked our way to the right side of the math. Each monster is worth a certain number of XP based on the level of the PCs relative to it. That's it. Then you count monsters. The XP budget is similarly easy to arrive at with fewer or greater players added as a simple extra lump of XP.
Its one of those changes in the math where it feels so intuitive it makes you wonder why it wasn't always like that, like you can't imagine going back and doing it the other way. Good job guys!
Using the XP chart to scale the encounters for 6 players felt really easy and elegant once I wrapped my head around it and printed off the tables.
Now to play the game and see how it goes... I added a zombie brute (level 2) to the 6 centipede room for 6 players... I'm concerned this was a mistake...