I, too, miss Inbox. I tried DarwinMail, but couldn't get it to work for me - I'm using Firefox, and when I tried to allow access, it appeared to work (DarwinMail had access according to my google account), but going back to the site said 'give access' and I went in a loop.
I'm not going to use Chrome (I know this is somewhat pointless as I'm still using gmail...), so is this a known issue, or am I doing something wrong?