Last day on the Allure and can confirm that no messaging apps we tried (imessage, google chat, hangouts) without Voom. We decided to hold off on the $2 Royal app texting until we felt like we needed it and made out fine without it.
We did get a one day pass on Voom to make a couple wifi calls, but that stream service was so slow - couldn't stream any videos or music in a reliable manner.