Chromecast has largely caught on as a way to easily use services like Netflix on your computer. MatchStick is an open source HDMI stick for everyone who wants to use there TV for more than just watching movies.
There's no problem with Chromecast per se it's just that Chromecast is a closed ecosystem that doesn't lend itself very well to experimentation. MatchStick runs Flint, an OS built on Mozilla's Fire OS. The platform is completely open so that developers can write their own applications for the hardware.
Importantly, because the hardware is open source its not bound by many of the constraints of Chromecast. For starters, that doesn't mean you need to be a partner with MatchStick Inc in order to use it. But other constraints also disappear,. For example, the phone you're using to talk to the MatchStick no longer needs to be connected to the same wireless network as the MatchStick. Want to use the MatchStick to power a link for photo editing for as a brudge so you can tether your Wi-Fi camera? That's easy enough to write.
The MatchStick devs I spoke to seemed most excited by the potential for more interactivity as well as multi-screen capabilities, both of which are very limited on the Chromecast platform.
Obviously, this type of open source language creates the "wait and see" problem where the potential needs to be realised by a bunch of people who aren't necessarily bound to the company. For its part, the MatchStick people say that because they're partnered with Mozilla, they're not exactly starting from scratch with a developer community.
Oh and as for your Netflix. MatchStick says they're talks with all of the big players in video. We'll have to wait and see what this little dongle's actually capable of when it's unleashed on the world next month.