[XorNot]

I don't trust TextSecure. It's too transparent. It is entirely unclear what happens if it can't send an encrypted message. It's unclear where and how much I'll be billed (important to those of us outside the US). And sans user authentication, there's no real trust model there.

[irv]

Feel free to not trust it, but it does indicate whether the message to be send will be encrypted or not: in the current version, a padlock will be locked or unlocked on the send button. If you receive an unencrypted message from another text secure user, it automatically detects the other party is using text secure and offers to initiate key exchange.

The billing criticism is fair and warranted; currently if your sending over SMS, the first message can only contain 60 chars due to protocol overhead, so you often end up with short messages costing multiple SMS.

There is a way to verify keys (manually!) but no indication that you have verified them.