In terms of specs and features, the POP 4 and the 4+ are more or less the same device, with the latter sporting a larger display. The POP 4 will have 5-inch 720p HD display, while the 4+ will have a 5.5-inch 720p display, but under than that, under the hood, the POP 4 and 4+ will be powered by a 1.1GHz quad-core processor accompanied by 1GB of RAM for the POP 4, and 1.5GB of RAM for the 4+.
The camera on both phones are of the 8MP variety. As for the POP 4S, the phone will be powered by an octa-core chipset and its 5.5-inch display will be accompanied by a Full HD resolution. Its camera will sport a 13MP sensor, and all three phones will have 4G connectivity along with Android 6.0 Marshmallow.
These are pretty decent handsets with enough juice to get the job done. No word on pricing or availability just yet, but given their specs we doubt they will be breaking the bank anytime soon.