Extensive connectivity and fixed battery
This time Google has not let itself be beaten about the radio standards: LTE, UMTS, quad-band GSM, dual-band WLAN according to 802.11a/b/g/n incl. ac, Bluetooth 4.0, NFC and GPS leave nothing to be desired. The battery is specified at 2,300 mAh and is supposed to allow a maximum standby time of 12.5 days - which, as with most current smartphones, is probably unrealistic. For calls it should be 17 hours, while surfing via LTE there are still 7 hours left; charging is wireless, whether there will be an appropriate charging station is still open.
Google sells the Nexus 5, which is shipped with Android 4.4 "Kitkat", via the Playstore: currently you can only buy the white version order with a delivery time of 2 - 3 weeks, which black version is sold out. Apparently Google has estimated the demand more realistically this time than for the Nexus 4, but the Nexus 5 should be available in regular shops from mid-November, so that you can save the 10 Euro shipping costs.