I have been running for a few days (since safedisk posted it on overclock.net - hats off to him) with my 10900k @ 5.1. It still comes with CPU microcode E2, so the "microcode updates" must be for rockit lake processors - I have modded the BIOS to microcode EC.
It is running great, no issues. May be best I have run, at least as good as anything else (I even flashed back a couple of older BIOS, 1003 one of them. and my overclock was stabler on the 2402, all things equal). I do adaptive all-core. Would get WHEA on same settings in 1003 with EC. YMMV.
So I am keeping it. I do think it is the best - at least for me.
There are no new features for 10th gen.
Oh yeah, there will be an Aura firmware update if you go update from 1003 (if you then flash back to 1003 the firmware will get updated back to the 1003).
Yes Alder is going to be expensive. And it looks like you will have to make a choice of Z690 motherboards that either support DDR5 only (ROG Maximus series) or DDR4 only. The DDR5 will be expensive and have a lot higher latency than the current DDR4.
ROG Hero XIII | 10900k @5.2 GHz | g.skill 2x32GB 4200 CL18 | ROG Strix 2070S | EK Nucleus 360 Dark | 6TB SSD/nvme, 16TB external HDD | 2x 1440p | Vanatoo speakers with Klipsch sub | Fractal Meshify 2 case