apart from price, any advantages over official google cast?
The obvious downside is OS upgrades and whatever else the manufacturer chucks onto that stick - could lead to performance issues, adware, malware etc.
This thing isn't cheap enough (relative to the original) to even consider buying.
Just get a Chromecast (make sure it's v2) and be done with it*
* most people I know who have a Chromecast seldom use theirs