For projectors with systems, there are two kinds of systems, Android TV and AOSP.

Android TV generally refers to a Google-certified Android TV system. It has built-in Chromecast technology, Google Play, and other Google services.

AOSP refers to Android Open Source Project. Many projector suppliers have developed their own OS for projectors based on AOSP.

You can get their differences by means of the table below.

                                                          Android TV vs AOSP

From the table above, we can see that Android TV performs better in terms of google service and upgrade.

The AOSP-based system may be better in terms of customized services developed by projector producers.