Our family started last year and have only been to Arapahoe Basin. Their bunny slope is VERY short, a joke really, so we didn't spend much time there. My son and I ended up making a couple runs on greens Wrangler, Sundance and the Chisholm Trail. With only our 4th day of boarding, we were encouraged by a local to try to make a run from the top of the mountain, so we rode the Lenawee lift and hit up Lenawee Face to Dercum's Gultch to High Noon, which are blues. At 35 and only a few days on a board, I didn't find these runs too difficult as long as you know how to do the basics.
I'm leaning toward Vail for our next trip in a couple weeks. They've been getting a pretty good amount of snow compared to other Summit County resorts. They also look blue friendly with plenty of long runs. I'm sure someone else with more experience will reply sooner or later.