Recs.
Updated
Specs
Pros
Pro Windows and Android apps
There are apps for both Windows as well as Android. This is beneficial because if you have a poor internet connection or low end hardware you can run Razer Comms on your Android phone instead of your computer, freeing up all the possible resources to maximize framerates in your games.
As a side bonus, you can keep chatting with your gamer friends even when on the go using the Android app (provided you have an Android phone of course).
Pro Chat rooms can be shared with voice chat users
To talk to others you will need to join a chat room. Then, from within the chatroom you can enable voice chat. This allows users with voice chat to still communicate with other users who don't have access to voice chat, and voice chatters can still type in the same conversation as the other players (both with and without voice chat enabled).
Cons
Con Razer Comms retire June 2017
Razer Comms will retire by June 1, 2017.
http://www.razersupport.com/software/comms/
https://linustechtips.com/main/topic/773578-bye-bye-razer-comms-the-voip-nobody-uses/
Con No support for Apple or Linux
If you have a Mac or are using Linux, you can forget about Razer Comms. It's unlikely Mac or Linux will ever get official support as Razer is traditionally a Windows-first company. This goes for iPhones too, while Android has a mobile app for Razer Comms, there is none expected for iPhones.