I'm starting to worry a bit.
I played with a colleague's "Developer Alpha" version of the BB10 OS, and I had a couple of observations:
1) In Alpha form, BB10 is more complete and less buggy than release-day WP8 was. It has a better music player, and the experience is just as smooth and sexy.
2) RIM took its time to "get everything right." They've ramped up hardware production, they have every major carrier in the US and worldwide supporting their launch (unlike WP) and there are unlikely to be device shortages, regardless of demand. They also spent time to fix and tweak every element of the software experience.
3) RIM is launching with over 100,000 apps in the BB10 store.
4) RIM is making it easy for Android apps to be ported over to native BB10. That means that apps like Instagram and others will be reasonably easy to develop for BB10, and will arrive for that platform long before we get them.
5) RIM, the principal hardware company for BlackBerry, is profitable (as of last quarter) and cash-flow-positive. Nokia, the principal hardware company for Windows Phone, is bleeding cash fast.
6) RIM is supporting carrier-independent OTA updates, just like Apple and Google. That means that any bugs that do occur can be fixed quickly, without a Portico-style "is my phone going to get it or not" mess.
I was super-impressed with the UI, slickness, and overall polish of BB10. I am getting worried... this OS could be good enough to push Microsoft out of third place.
Microsoft needs to step up its game. Third place is NOT guaranteed.