GroupMe

Syncs so much better than GroupMe for 8, and inline quick replies from the notification center are a great addition. It has no problem handling my 10 groups simultaneously.

This app is vastly improved over the horrible WP8 version. However, there is no video posting. Add it and it's five stars! (note I have edited my review and added a star because they added several other featured I noted were missing... keep it up!)

Group me has the best UI design I ever seen on windows phone. It is really feel stable and easy to use.

I've tried glide, cyberdust, snapchat, WhatsApp, Viber, skype and for texting and exchanging of multi media, this is by far, the best thought out app out there. Wonder if there's some way to leverage this service and make skypes app a little more "hip"