Some have compaired this election to the massive sweep that occured in 1994. Others think it will look much more like the 1974 election. The conditions in each and every election are always somewhat different.
Some mid-term elections especially in the second term of presidents you have a massive wave other times you have a moderate wave like 1986.
Given all you have seen from the many different polls and your own gut reaction what past mid-term is this election likely going to look the most like. If you think this year will be very different from any past mid-term you can say that as well.