I have and shot both. I will say, i may have gotten lucky but the Mossberg shot great in two load attempts. The Rem took a bit longer to figure out. Both shoot amazing now, i don't feel ethical shooting at turkeys at the distances these guns could do it.
Mossberg pros: made for turkey hunting (over bore = less pellet deformation)
Cheaper
Readily available chokes/replacement items (stock, sight, scope base)
Cons: kicks like an ill tempered mule (i only shoot it once a year, i forget how much it kicks by then)
trigger gritty, not important with turkey hunting in the moment
Rem Pros: more robust sounding and functional build (feels better)
Readily available chokes/replacement items (stock, sight, scope base) (maybe the most common shotgun ever)
Find them anywhere
Cons: More Expensive compared to the Mossberg
Can take some work to find a load, I own 4 and 1 came ready to play, 1 took a few chokes to find one that it liked, 1 took a ton of work (lengthen forcing cone, polish barrel, high end choke, hand loaded shells) to get to the turkey killing levels i want