[thrilleratplay]

The only compromise I see with open source Android is the proprietary firmware blobs. With the exception of http://www.replicant.us/, this is true for most open source mobile operating systems. Cyanogenmod adds in closed source analytics but those parts can be removed with https://github.com/nvllsvm/freecyngn

While I cannot attest to daydream, I have happily been building a custom version of Android from source for years without Google Apps or other closed source applications. Everything I need is either part of Android, on Fdroid.org or Github.