Andrew bought a Nexus 7 Android tablet for his birthday and he's running into issues with SMS text messaging. Leo says that SMS is the short message service between wireless telephones. So it wouldn't work. But he can use apps like What's App to do it. He may run into issues because he won't be able to universally text to phones with it. The chatroom says he could get Skype, which works great on the Nexus 7, and he can buy the ability to text through Skype. That's a good option, as is Google Voice. Even Google hangouts would work. TalkaTone is another.
Andrew also says that some apps on his Galaxy S3 won't work on the Nexus 7. Leo says that unless they're written to be universal, he'll need to look for a tablet version of the app. If the app he's using is Samsung specific, which would be the case with the S3, then it wouldn't work on the Nexus 7 at all.