There is a difference. I am a die hard fan of 870s and have one that my father won in a duck calling contest in 1953! In the ensuing years I have owned dozens more in every model imaginable.
However, when I was a teenager, the gun of choice for 'sports' was a winchester m-12 pump. It does not have a disconnector. you can hold down on the trigger and shoot it as fast as you can slam the pump action back into battery. The 870 has a disconnector and one must release the trigger(let it go forward into reset) before firing the next round.
Yes, you can shoot a Winchester M-12, Remington Model 30 or Ithaca Model 37 faster than an 870. However there are more important features that make the 870 a better gun for me.
As a teenager, I used to work duck clubs during season in the Stuttgart, AR area. I always carried my M-12 because I was so proud of it and just knew that it made me more of a sport that someone carrying a lowly mossberg, savage or Remington.
I used to make more money wagering with dude hunters than my fees and tips as a dog boy or decoy boy. When I spotted a dude carrying a shiny new Browning Auto 5, I would wager him that I could put three hulls on the floor of the duck blind from my M-12 than he could with a Browning Auto. Folks, this is a sucker bet. The Winchester pump can get off three rounds a lot faster than a recoil operated browning auto. I always picked on dudes with new hunting clothes recently purchased just for this trip and shiny new guns that indicated to me that these folks were tenderfeet. I learned to keep my mouth shut around hunters carrying gas operated autoloaders. I learned that I was the sucker trying to out shoot these guns.
With the old guys that did not shiver in the blind and wore old canvas hunting clothes and carried well worn M-97s or Fox double barrels, I remained deferential. kept my mouth shut and fetched their coffee and brandy and downed ducks.
Nothing like getting up at 0300 and breaking ice with my waders to put out decoys.
The only gun that I will take out in the woods is an 870 Express. I once dropped a Perazzi on the ground at a skeet range. It cost me over $600 to repair the forearm and fix the ding in rib. To do $600 worth of damage to an 870 Express, I would have to leave three of them on a railroad track.
I have used an 870 express to paddle a boat, tighten barbed wire and as a jack handle. It will still shoot better than I can point it. Faster than a pump without a disconnector, Nah, but speed does't count as much as accuracy and dependablity.