miles of cruisers, scenic, excellent layout, nice village nearby
not very challenging
Okemo is first and foremost a really fun place to ski. When we were there (just before Christmas 2009) there were no lines and essentially uniform conditions on every slope -- groomed New England hardpack, with little or no ice. The gradations of difficulty between green circles and black diamonds is razor thin -- there's barely any difference between them! I would imagine the only characteristic that really distinguishes the trails is how they're groomed. Every single trail we skied, from green to double black, had a nice, gentle pitch, twists and turns, and was basically a cruiser. (Note: the gladed stuff was all closed when we were there; maybe that invalidates some of what I just wrote.)
Even though Okemo is a pretty sprawling place, with several sub-areas shoulder-to-shoulder, it's beautifully laid out. You never have to ski uphill or even skate on flats. We skied downhill 100% of the day despite going to and fro between the main area and Jackson Gore several times.
There are lots of long almost top-to-bottom cruisers here that are just a pleasure to ski. You can turn wherever and whenever you want because there's nothing in the way, ever. There's enough pitch to get you going but not enough to be challenging. Just lay your boards down and let 'er rip.
Having skied Colorado, Utah, and Wyoming, in terms of challenge, Okemo is not even on the map. It's from a different universe -- one in the shape of a blue square. But man is it fun. It was so cold my nostrils froze, but I was grinning from ear to ear. Okemo is awesome.