File married jointly or separate?

[Ben Kirchner]

My wife and I keep our financial accounts seperate, and simply share a mutual credit card that we equally contribute to for mutual expenses (mostly groceries).  I purchased 2 houses with my own finances in 2017, which are completely in my name.  Would we be best off filing separate?

My wife and I got married in 2016.  She had $0 taxable income in 2016, but now has a full year of taxable income in 2017.  I will also note that my wife and I are purchasing future investment properties together, starting 2018.  

Would I be best off filing as separate?  Any advantages for filing jointly?

Thank you