I've never done any legacy BB development, but coding for the playbook / BB10 is pretty excellent. Write C/C++ like you normally do for any *nix/Qt type system (using the Eclipse based IDE); Compile locally and deploy over the air to the device; stdout/err get sent back to the Eclipse console. I remember being really surprised at first at how easy it was to rip through the build/deploy cycle. The dev kit is pretty well done.
I can say with certainty that there is no RIM server involved beyond getting a Dev cert at the very beginning. You can develop offline and deploy over an ad hoc LAN or USB - so there's no requirement for Blackberry to sign your dev builds.
Anyway, if you haven't looked into it, do. There's also a bunch of BB folks on github porting libraries and such to BB10, so if the library you want isn't in the SDK, it may already be ported. Though in my experience it's pretty easy to just build most vaguely POSIX compliant code yourself.
It's good to hear they've improved the development experience. It was something that I think that really hurt them in the past. I will have to take a look into it when i find the time.
I can say with certainty that there is no RIM server involved beyond getting a Dev cert at the very beginning. You can develop offline and deploy over an ad hoc LAN or USB - so there's no requirement for Blackberry to sign your dev builds.
Anyway, if you haven't looked into it, do. There's also a bunch of BB folks on github porting libraries and such to BB10, so if the library you want isn't in the SDK, it may already be ported. Though in my experience it's pretty easy to just build most vaguely POSIX compliant code yourself.