Just sharing, being not willing to splurge hundreds just for doorbell cam that most shared in here (had Xiaomi security cam covering living room entrance anyway), I bought this China (or Hong Kong) Eken V7 doorbell at ~$50++ for a try
It's using Aiwit app (developer from hongkong I think). Tested playing for awhile and all seems pretty good. Doorbell triggered notification/call in 1-3sec (for both WiFi & mobile network on phone)
Free cloud storage 7 days rolling. Live video feed latency of about ~1sec after initial 2-3sec loading. Intercom voice latency ~1sec. Up to 3 users for viewing cloud recordings, just 1 user access at any point of time for live feed/intercom.
PIR motion recording I've yet to play around with the sensitivity to find best optimal setting.
Powered by 2x 18650 battery, rechargeable via microusb port on detachable doorbell (can be secured via 2 tamper proof screws at bottom). Chime is wall plug, 30-40 melody. Both bell & chime volume adjustable.
From others reviews, battery last around 1-3 month (depending on PIR sensor setting and usage). Shall see how it lasts.
Overall, am actually surprisingly satisfied with it, at least for now haha