Is there much difference in terms of weight, reliability and perceived recoil?
I prefer the Mossberg for the following reasons:
The lifter is up on the Mossberg with around chambered, down with the Remington. This makes reloading easier on the Mossberg.
The safety is on the top on the Mossberg where I can see it, down by the trigger on a Remington.
(This is a disadvantage for the Mossberg if you insist on having a pistol grip stock. I don't like PG stocks, so it's a non-issue for me)
Out of the box a Remington Express is slightly smoother than a Mossberg, but this is easily corrected if you know which side of a gunsmith's stone to use.
Some count the steel receiver of the Remington as an advantage over the Mossberg, but since I've never heard of a Mossberg receiver wearing out or breaking, it seems that the only difference is that the Remington is heavier.