The Winchester 1300 is, IMHO, the best pump shotgun made. I currently own 2 and always keep my eye open for another one at a great price. The only bad thing about them when compared to an 870 or Mossy 500 is that there are not as many aftermarket options available. You can still get tubular mag extensions, a wide range of barrels from 18" to 30" with a number in between, slug barrels.....the list goes on.
Have you shot it yet? You may find that you like it just the way it is. What are you planning to use it for?