Oh I got it. But that was not enough for me to Sign Up. I still need to know... - on which devices will this work? - what email hosting / APIs does this supp

Oh I got it. But that was not enough for me to Sign Up. I still need to know... - on which devices will this work? - what email hosting / APIs does this support? - do I like the UI? - do I like the web site UI and think it'll translate to the app... ? - does this cost me something, such as a subscription or time clicking through ads? - will I actually like this UI for my email over what I do now?