I was given a booklet with excerpts from the lectures of Rabbi Shaul Yitzchak Rabinowitz of Satmar. The booklet is in Yiddish with English translation.
The gist of his message is, treif phones - which are phones that enable you to do anything but make and receive calls - are a danger for the Jewish family. And they are dangerous even if you don't own it but people in your circles own them. The fact that other people in your community own them, and that your children's classmates either have these phones or their parents do, means exposure to danger.
Even if a person does everything right and has a filter and it's used only for business, experience has shown that that it is impossible to control the people around you. Children are drawn to these phones, even if they only have the ability to text, and all the more so if they enable images.
Parents might think it's nice to show their children Lag B'Omer at Meron on their phone or other innocuous or even wonderful things. What the booklet says is this teaches children that nowadays, the prohibition against viewing images is no longer in force. Your children will likely be less careful than you are. (Perhaps these are the people seen in the public libraries looking like ultra-Orthodox Jews and checking out CD's of movies and TV shows).
He claims 30% of children own treif phones and are going downhill and taking others down with them. He says that even for business purposes it's not worthwhile to have these phones because the benefits of the phone cannot compensate for the damage it causes.
He sounds very serious and is raising the alarm about how our children are being ruined while many other frum Jews who are serious about chinuch are focused more on filters and safeguards like Web Chaver. It's certainly something to think about.