I have a nova in a 26 inch barrel , and love the way it points - I would like to mention it is a Italian style profiled barrel and this tends to be lighter than most 26" american counterparts - I suggest if you are at a store try a 23 or 24 inch Mossberg or Remington and shoulder it , and then compare it to a 26 inch Nova and you be the the judge on the pointing abilities - numbers are just a gauge for reference see what your shoulder tells you
A longer barrel will provide , a longer sighting plane , than a shorter one -
Conventional wisdom will indicate that a slightly higher velocity with a longer barrel , depends on the load -some say a increase of 8-12 fps per inch ?
Still shoot people like the longer barrels , I don't think its because they inherently shoot worse, proably the other way around - but members have tweaked with their setups to get some outstanding results with shorter barrels