> In my opinion the signal ios client is significantly less polished than the telegram client. I could convince my girlfriend to switch to telegram, after she found signal to be intolerable on her android device as well.

My reaction is the opposite. I love the signal iOS app because it doesn't try to do SMS. It lets you enter the code which is great if I want to use a Google Voice number instead of a carrier number (and I don't forward Google Voice texts to the carriers). I am not a fan of SMS fallback and I am glad I get the "Enable Signal for SMS" on Android as opposed to just sending a text.