Still as of version 2.3.3 in June 2016 Signal app will not let you proceed past an initial request to grant it access to ALL of your contacts and to provide your phone number. Uh.... resounding NO.
There is no functional reason why the app would need access to all of your contacts, or your phone number, both requirements to even use the app. The only logical conclusion is that they force users to give their phone numbers and contacts for some reason other than for the app to function as a messaging platform. Who knows what those reasons are, but we can rest assured that theyre not good reasons.
Until they make this optional then I will stick to other secure messaging apps. That being said, I hope they see the stupidity of this approach when trying to woo people concerned about privacy, and eventually do the right thing. If/when that day comes, Ill give it a try.
fugly_mofo about Signal - Private Messenger, v2.3.3