From what i can tell the best use for this teewe device is to stream youtube content to your tv from a mobile device. Even full hd YT content is pretty compressed and will fit within n150 streaming limits. The catch is you can't access 1080p content any longer from a mobile, its 720p only. Only pc's can access higher than 720p.
Or to play music from your mobile to the tv. It wifi enables a 'dumb' tv to a certain extent.
You will not be able to reliably stream any offline high rez full hd media. In fact this thing will have trouble streaming 1080p 60fps video shot from mobiles. 30fps 1080p only and below will work fine. Teewe is for people with simpler requirements than the OP.
Here is the important
bit
Wireless Standards: 802.11b/g/n Wi-Fi (802.11n 2.4GHz only)
It's n150, had it been ac the throughput would have been 3x higher. Not worth buying dongles unless they offer ac or are at least 2x2. some of sony's recent tv dongles are 2x2, expect samsungs are the same too. Since teewe does not have a wifi cert by the wifi alliance its by default n150 and not any higher.
wifi ac will cost much more but will be more useful but router needs to be in the same room as the tv. for these kinds of devices that interact with mobiles, ac is ideal as you will always be close by with no walls in between to attenuate the signal. Course you need a mobile that has ac too.
I'd give the edge to the chromecast as it can screencast in addition which teewes does not offer. The only reason this device has a purpose in life is because chromecast isn't easily available. But chromecast is also n150 too, the next update with wifi will hopefully be better.