Both printers include colour printing, Wi-Fi connectivity, and USB connectivity. Their most relevant distinctions are ISO black print speed and automatic duplex printing.
ET-4950 has ISO black print speed of 18 ipm, versus 11 ipm on L5390. ET-4950 supports automatic duplex printing, whereas L5390 does not. ET-4950 supports automatic duplex scanning, whereas L5390 does not. ET-4950 has replacement black ink yield of 7500 pages, versus 4700 pages on L5390. L5390 has replacement colour ink yield of 7500 pages, versus 6000 pages on ET-4950.
The paired specifications favour ET-4950, particularly on ISO black print speed. The other model may fit better if its own strengths matter more to you. Consider the first model if replacement colour ink yield matters most; consider the second if ISO black print speed is the priority.