Get a 6.1 block if you can find a good one at a fair price.

New blocks require a cheesy cam phaser lockout and there's no after market timing sets available to eliminate the cam phasing mechanism and OEM timing chain all together. There's also a specific cam core needed because of the related cam phasing BS that was done to the block.

Has anyone measured the quality/accuracy of the newer OEM machined blocks vs a block machined by a good machine shop?

There's a reason the OEM 6.1 blocks are still in high demand (and very expensive) and why the aluminum performance blocks are based off the 6.1.

Be careful when offered the cool-aid for the newer blocks...

A newer block will work, just be aware of the never ending Mopar band-aids and fixes needed to make something work outside of a production environment.