Excellent looking site and I love the way you used the columns!
Ok, the ezcol-divider gets inserted after a run of columns in order to clear the column floats, otherwise you can end up with some undesireable results with content layout. I also use the :after pseudo class to insert a "." after the last column with a clear:both style, but that seems to work differently from browser to browser. I'll ensure that the next update (within a couple days) sets the height of the divider to "0px !important".
In looking at your layout, I see that there's a
under the 1/3 columns, and then there's a <p></p> under the 1/4 columns. To be honest, I think the spacing is fine and found no issue with the look at all. However, if you want to remove the spacing, I'd look there and make sure that you don't have any carriage returns that WordPress' AutoP filter will convert to <p>'s.
Hope that helps!