Maybe it's just me being lucky, but I don't understand all the complaints about WhatsApp, unless the WP8 version is really bad compared to the WP7.x version. I've had WhatsApp on BBOS and have it on WP7.x, and I never have any issues with notifications. I've used it to chat with people in Canada and India not just those in US, and they never complained about it either (various platform contacts have it). I even belong to a WhatsApp group made up of people originally from a BBM group. I don't recall any of my WhatsApp contacts on any platform complaining about WhatsApp. My suspicion is that many complainers probably have a crappy data connection, whether mobile data or WiFi. Crappy data connection would explain the battery draining from WhatsApp, in addition to the lack of notifications. Anytime data connection is bad, that will drain battery.
But Augie is right that the forum complaints, especially about WhatsApp aren't limited to this site. CB, AC and iMore also have a lot of WhatsApp complaints if one searches those forums. I don't know if webOS ever had WhatsApp.