The .376 is in the same pressure class as the WSMs as you note. I have both a Scout and Pro Hunter in this caliber and both seem to generate better velocities (i.e. they seem to have fast barrels) than the load data in the Hodgdon manual suggests they should. With the Hornady 225gr bullets and two grains off max with Varget I get the same velocities as as they list for the max load and this is out of a 20" barrel. I think its a good cartidge but I think they made a mistake in naming it; they should have called it a .375, which it is.

I don't know what to tell you about the Dakota. In my experience, they are a good gun but there are periods where they seem to have had quality issues. Mine is a 1988 gun and is exceptionally well built; its very smooth in feeding and extraction, the trigger is excellent and it puts out 3-shot groups with all holes touching at 100 yards. I also got a very good deal on it which didn't hurt. If you are really interested in it, look it over in person before buying.