I just gave it a shot and it looked like the install worked fine, but the control panel loaded up with a bunch of errors. It looked like they could likely have been suppressed by turning off E_NOTICE or changing E_STRICT in error reporting since they didn't look like errors that would stop anything from working.
Been running EE3 (3.3.3) with php7, and it runs smooth as a baby's butt.
There are a whole lot of problems with add-ons tho I've realised.
Solstice TAG throws a nasty error making it impossible to add new entries.
DataGrab is not working (Well, the UI is, but no imports are made, and no import-setups can be saved).
Don't know about any other add-ons (...