I tried to make a decision and couldn't, so I did the right thing and got both!
Mossberg 500: (also has a 26" barrel with multiple chokes)
The Remington holds 1 more shot than the Mossberg does, but they both shoot great. I like the location of the safety on the Mossberg, but that's because the 20 ga. pump I grew up with was a Mossberg too. You really can't go wrong with either choice. I will say that the Remingtons are easier to obtain parts for and to customize than the Mossbergs are.