1) We wrote it and we're an entire group of uptight corporate types who review and test everything to death.
2) We will be versioning and releasing differently.
3) Using our stuff adds an additional counterweight in the whole NIPs discussion, so you would have representation without having to spend all day stalking NIP specs.
4) There will be OnlyUs features included and you can influence the design.
5) It is written in C/C++.
6) We have Nostr-native customer support, over GitWorkshop, and we are responsive because this is basically what we do.