I have gone from another provider and a HTC phone to AT&T with a LG G2.
I used messaging extensively to communicate with different groups several times during the week. But the new phone doesn't allow messages to more than 10 persons. As well, the phone does not allow me to make preselected groups that I used continually. (You have groups, but to send a message you have to select the number of each contact every time.)
I have checked out some other messaging services - Groupme, LTD Messaging and Viber - but I do not see that they have the way of making the groups that I need.
There is no instruction with LTD Messaging and I cannot even set it up.