I frequently prefer FB Messenger because it is both desktop (web) and mobile, and it handles media. There are other cross-platform messaging services like Google Hangouts (GChat/GTalk), but I still can't attach a photo. Or there are ones like WhatsApp that focus on mobile, and are missing desktop/web. Apple iMessage is good, but it's only usable on iOS devices, which is not always what I'm using. And other cross-platform messaging products don't really have much adoption.