Breck in January vs. late March- OK here's my $0.02:
Snow aside, you're looking at bone-chilling temperatures in January, I've ridden there in -30 windchill and there's a reason it's called Brecken-fridge. Late March is variable, can be warm and sunny, t-shirt and spring weather, can be cold, overcast, and snowy.
It's a perfect place for a first trip out west, a straightforward drive from DIA, nice structures in town, plenty of places to stay and eat, amazingly well-kept slopes, excellent park. . . And if you get tired of Breckenridge, there are lots of resorts in the area to choose from. You can't go wrong.
The snow situation- Summit Co. with the exception of A-Basin and maybe Copper, is a dry spot. I think the reason for this is that the systems dump their snow around Vail Pass, and you get a rain / snow shadow east of there (Breck, Keystone).
If you're looking for challenging terrain, go to Utah or Tahoe.