Title says it all. The C40ii has the most comfortable neck I've ever played. Love its depth, love its shape. (The satin finish is a nice perk, but not necessary.)
I've been playing seriously for about 2 years and have only been able to test maybe 30 classicals in that time period. I've yet to come across another guitar that has the same neck profile. The other contemporary Yamaha's I've been able to get into my hands have been much thinner, which seems to be the trend these days.
All solid would be preferable, but I'm okay with laminate back and sides.
EDIT: I guess this profile would be considered a U shape?