Are we already Viral ...?, page-7

Most of the reviews are 5 star or 1 star. Seems like they love the app once they're online normally and people who give 1 star haven't actually used the application or can't get it working.

A few reasons:-

1) People aren't patient sometimes the pass code can take a few minutes
2) They're entering their phone number in wrong and not checking it (you'd be surprised how many people ignore the messages saying not to enter it with their country code)
3) There's an actual problem with the delivery of the password that seems to be only affecting certain users. (Possible - or it's an issue which keeps cropping up)

Either way it seems like if they get registered the feedback for the core functionality is overwhelmingly positive.

Keep in mind people tend to only leave reviews when they want to complain. (But not actually make the effort to contact support before having a whinge)