D-LINK DIR-868L is a N and AC wifi router from D-Link with a built-in 4 port gigabit switch.
 Problems with this router
This router works just fine as a pure wireless N and AC router. It's got a rather short range on the 2.4 GHz band compared to other routers but it does work fine. It's totally alright as AC router.
This router will work very badly as a switch and using it as a switch cases big problems with the WIFI.
If you connect this router to two computers using gigabit cables and copy a few big files from one to another then all the WIFI clients will disconnect from it and it won't accept new WIFI clients until this router is rebooted. This means that you basically can't use this router as anything beyond a pure WIFI access point.
You should absolutely not buy the DIR-868L router or other D-link products. Using the gigabit switch part of a WIFI router should not disconnect wireless clients and permanently kill the WIFI part until it's power-cycled. This is just a total scandal. Keep in mind that this is out-of-the-box behavior for this router.
 Expected speeds
You can expect about 3 MB/s to your average mobile phone over 2.4 GHz and 4-5 MB/s over 5 GHz.
Modern laptops with 5 GHz AC will get about 40 MB/s.