Here's what I think makes these chairs so comfortable: first, they are really well sculpted and feel really natural when you sit in them - they sort of take the weight off of your butt because of the way they distribute your weight. They also have a really nice natural rock angle to them. Some rockers sit you up really straight which is awful, while others pitch you so far back it makes your neck hurt to read a book. This one has the perfect angle. Also I like the heavy substantial feel of the whole thing: the slats, the armrest - everything feels really strong and luxurious, unlike all these cheap Chinese rockers that all the big stores sell. The ones that creak and bend and then break.
By the way, I can't recommend the Y Camp highly enough. This place is just gorgeous; it's right at the entrance to Rocky Mountain National Park and they have what looks like hundreds of cute cabins you can rent, plus several lodges - and loads of things to do for the family in addition to all the amazing hiking everywhere around it. The view of the mountains from the rocking chairs on the porch is to die for.