There have been some CVEs, but all the exploits I'm aware of already had patches and were only exploitable for un-updated models.

I honestly don't know what you mean by not invented here. They did create a wireless protocol for point-to-point products with some advantages for those who opt into it, but that's the only thing I can think of.

Sometimes their documentation is lacking, but generally their docs are very good.

If you need a more advanced AP, you probably shouldn't be looking at all-in-one devices. Buy separate components, add as many APs as you need for proper coverage, rather than relying on a single device to cover everything.