For those of you who own a Day or Hobo better yet both....

The day is definately bigger than the hobo, I'm sure that there are comparison pics somewhere in this forum. The hobo has a longer strap and is more rounded at the bottom whereas the day is more rectangular and the bag sits around 6 inches or so below your armpit. The hobo should fit all your essentials as well as the day.
 
I like the new Hobo much better. It's more comfortable and it doesn't have that feedbag look. The Day never has been and never will be one of my favorite styles. The strap hurts and it's just so darn long and so hard to get to things in a hurry.
The new Hobo is plenty big buyt much easier to find things and it's no heavier than the Day even with the GH.