Joining voice calls is reliable, and shared screens functionality works well on the app. The major frustration is chat. Chats from colleagues dont appear unless Ive initiated the chat and keep the app open, theres no working chat history, and contact search does not work for my organization. Mine is a 150,000+ employee professional services firm, and we need a reliable chat service on the go. This is NOT it. To offer blame where due, Skype and Lync also had serious and similar chat limitations before the acquisition. With so many alternatives in messaging, Im shocked neither team independently, nor the SFB folks now, are capable of solving this problem.