Screen mirroring (at Samsung: Screen mirroring) works well for strong buy recommendation.

There are now a large number of such devices. It is skeptical, because often negative rating. I do not regret buying the HAMA HDMI dongle and would also recommend it to others in the same application goals. My goal was to mirror the screen, not movies * to transfer. The operation is easy (depending on the playback device, read its instructions!). The connection is established normally via Wi-Fi Direct, which keeps the wireless connection to the router unloaded. Alternatively, the dongle can also be integrated in the network for DLNA playback.

* Standard definition video still run (slightly delayed, sometimes slight judder), HD (eg 1080i) I have not tested. (Since I'm just realistic as a technician ran and watch me the data throughput of HD recordings on! Realize Per WLAN N hardly.)

If you have problems you should consider what radio interference sources are still close first. For me that was the solution for initial difficulties (eg Bluetooth on the device off). In the office, it worked with the smartphone, the tablet, the picture was pixilated and initially was almost entirely. Then the TV (there is no other radio interference sources), everything went without problems.
1 point deduction, because these information are in the manual. But there you will find no really viable evidence on the operation. I assume that any existing noise sources often is the reason for the often conflicting reviews of such devices.

Tested with the following devices: Samsung Galaxy Tab 10.1 Wi-Fi 4 (Android 4.4.2) and Samsung Galaxy S III (Android 4.3)