You might want to call the bus company to inquire about updated schedules and reservations (long shot, but sometimes possible):

http://www.beijingchina.net.cn/beiji...o-baoding.html

In terms of comfort, I assume those shuttles use the same ~60 seat passenger buses that are common at airports and for medium distance inter city trips. Luggage storage underneath, acceptable seats, maybe a little bumpy in the rear section.