Both printers include colour printing, Wi-Fi connectivity, and USB connectivity. Their most relevant distinctions are fax and an automatic document feeder (ADF).
L5390 offers print, scan, copy, and fax, versus print, scan, and copy on ET-2856. L5390 supports an automatic document feeder (ADF), whereas ET-2856 does not. ET-2856 supports automatic duplex printing, whereas L5390 does not. L5390 has ISO colour print speed of 6 ipm, versus 5 ipm on ET-2856. L5390 supports Ethernet, whereas ET-2856 does not.
The paired specifications favour L5390, particularly on fax. The other model may fit better if its own strengths matter more to you. Consider the first model if fax matters most; consider the second if automatic duplex printing is the priority.