The only thing is: Since it's a custom android skin, your not going to be getting updates regularly. Whereas with Windows we have the insider preview.
Not quite as simple as that though.
Security updates are very prompt. (I get them within a day or so of rollout every month, which sometimes beats Google pushing to their phones)
Major version updates take longer though since BlackBerry messes with it under the hood and that's a negative. I believe there may be a Beta program actually, but don't quote me on that, I don't think Nougat is in there anyway.
Also, Insider Preview isn't a great comparison since it's beta quality code. I would just compare to MS's control over Production where they push a cumulative update monthly and can still put out major updates.
But on the other hand, we can talk about the new features that will be added in say Nougat vs. the competing W10M release and I'm pretty sure even a delayed BlackBerry Nougat would have more new features in the same timespan, (ignoring anything BlackBerry may add) but of course, major iterations are slow, security ones speedy.
(although we're certainly behind the faster releases of Nougat in other devices in Android-land like the Nexus 6P)