The older Winchesters were decent guns, but the current made somewhere overseas version is unproven. The Mossberg is "good enough", but not an 870.
The Browning and Benelli are actually good choices and an option to consider. As a lefty the Browning has a true tang safety. The Mossberg is mounted on top of the receiver where it is in the way of both right and left handed shooters. The safety on the 870 is no problem for lefty's, but the Benelli might be more of an issue.