Either or, that 1.5" won't matter a lot, but the extra ammo in the tube will make it heavier by the muzzle which might be useful for negating recoil, but I find they are not as handy to point. If you want a shorter LOP and a shorter gun overall, plus being able to easily find other barrels, the 5-shot mag tube 500A or Maverick 88 is the by-far easier Mossberg to find barrels for and will be lighter and shorter.
590's are great guns, but if you don't have other specific plans for the gun than HD, a 5-shot 500A is going to serve just as well with much less initial cost. If you want a 590 go ahead and get one, but honestly, for Home Defense duty, it's not necessary.
If you plan on using it for hunting, you might be limited to 2 rounds anyway depending on your state regs.
Call me old fashioned, but an 18.5" barrel M500 with a butt-cuff and 5 extra rounds on it suits me just fine. You are not planning to repulse an invasion, just eject a burglar. Odds are it won't ever be fired in anger!