I don't think it is ready for release, and that is the reasons for delay.
The 10162 I have still has sound card issues and driver issues. DirectX seems to be having difficulties, some of my Legacy software still doesn't run properly. And Edge isn't even fully enabled. I think that the Insider group will be far more forgiving then the general public, if problems arise. I don't think they should have announced a release date without having a completely stable product. I have a feeling this is going to be a messy release. And again, since they haven't given any pre-order numbers, I think it may not be in as great as demand as hoped for.
Different Microsoft management, but IMHO and those of other PC gamers I know, Windows 7 just simply worked, no issues. And that's the reputation Microsoft had. Windows 8 wasn't bad but Windows 8.1 was a fiasco. Ethernet wasn't working, wifi was dropping out, sound needed work arounds because 8.1 drivers weren't ready. They even passed through a very old driver for my I7 980X which didn't work. There were numerous posts about these issues on the Microsoft forums. The text book answer being "we are not responsible for third party devices and manufacturers updating their drivers". Really? Everyone knew the issues were specific to 8.1 and weren't happy with that response. Seems more effort was made or more time was allowed to let third parties get on board with the os' before 8.1. And if additionally there are Direct x 12 issues in 10, I think Microsoft hopefully learning from the 8.1 release, would be thinking it's very wise to delay the release of 10. Microsoft ONE's position is one os. Laptops, etc might be easy. But based on the "ONE" philosophy, they shouldn't release 10 until its working without common issues for all users.
Is it ready? I have no clue, but I am reading recent posts about similar issues that 8.1 had. I agree with Trust. A release date shouldn't have been announced unless they have a completely stable product, or if they are 100% sure they will achieve that by July 29. IMHO, they certainly did not have that with the 8.1 release. They need to do it better this time and take all the time they need to achieve that. If there are issues like Trust mentions, I certainly hope they do delay as opposed to the strategy they took with the 8.1 release.
If anybody's looking for perfection, specially with new edition is an optimist. Most of updates, except those for security are mostly fixes specially service packs. So mostly ready windows is expected, nothing more.