I have not had issues with group texts or sending pictures. The biggest thing you need to know using the android messages (new name for google messenger) for group texts and pictures they come accross ad MMS (multimedia) where as just normal text is SMS (simple media). There is a setting in android messages under advanced for Auto-download MMS and Auto-download MMS when roaming. These need to be turned on or you will get a text asking you to hit a button to download. if you have these on the message with download automatically when it comes in. Having this on helps with group texts.
Also on 3.0 republic wireless just improved texting reliability with giving permission to the republic wireless app to see text messages. if the message doesn’t send you see an alert where the republic wireless arc normally is. that way you know you have a failed message. i have only had this happen once since they upgraded the republic wireless app.