I'm 1" taller and 2 lbs heavier than you and personally I think the large hobo is too big for me. It just depends on if you like the way large bags look on you - it's all personal preference - no right or wrong. I have both bags, although my ergo is a medium. I love both! Sorry I'm no help!
It all depends on what you need to carry. I have both medium and large ergos along with the medium ergo tote.
I usually take the large hobo on those days when the entire world will end up in my purse. I like the large because I can even carry an unmbrella around with me and living in New Orleans you never know when it will rain. Since the bag isn't structured I can stuff whatever I need like toys for my niece, snacks or a drink and the camera for our outing that day. I am also 5'3" and since the bag doesn't hang low and kinds of flattens when it isn't full of stuff I don't think it overwhelms me. You may want to compare the measurements to something you already own to see how it would work on your frame.
On a normal day I'll use the medium ergo which fits my normal things.