Here is a TL;DR Summary of Chillout VR vs. VRChat

Chillout VR:

1. No Anti-Cheat built in at the time of this video being recorded.
2. Mods are allowed by Alpha Blend Interactive as long as the mods used are not malicious.
3. Avatar Encryption
4. No Ranking System
5. You can directly search for avatars.
6. Currently not Quest compatible. PC VR use only at this time.

VRChat:

1. Easy Anti-Cheat required. Depending on who you ask this can either be a good thing or a bad thing.
2. All mods are prohibited by the VRChat Dev team without any exception.
3. No encryption whatsoever for the avatars at this time.
4. Has Ranking System
5. Sorry, no direct avatar search here.
6. Quest compatible. Expect lots of kids here.

That's just off the top of my head. There are a lot more differences between these two platforms that I simply can't explain in one description. Some of the differences are too technical for me to understand, let alone explain.