This thread is no longer real fresh but I'll add my experience with Blaschak bagged nut here in Berks county, Pa.
Been buying it from a hardware store near Fleetwood, Pa., for about the last 5 -6 years.
The bagged nut until Fall, 2011 was a lot closer to pea size with a few larger pieces and some barley sized and fines. Very wet. White to pink ash.
Worked ok in a Warm Morning 500 and before that, a small very old cannon heater. Now have a Ds 1400. The fines and small sizing occasionally gave me some trouble. Usually paid about $5.50 a bag in heating season and $ 4.50 in Spring to Summer. 40 lb. bags.
The Blaschak nut I started getting in early Fall of 2011 was a lot different, A lot of stove size and nut mixed. Still fairly low ash. Seemed a little lower heat ouput to me. $ 6.00 a bag, in bulk, $ 7.00 in small quantities.
This year ( starting late summer) I was sold obviously old stock with stained and dirty bags and water running out of all the bags. Likely stored outside and was the older undersized stuff. Next 2 pickup loads this year were the newer stuff. Burns well. The Stove/nut mix with a little bit of smaller stuff seems about right.
I have a source of bagged Reading that I have tried a couple time. I know they had some complaints and bought a lot of it 2 or 3 years ago. The nut runs mostly stove size with plenty of fines and very wet. They sell 50 lb. bags for $6.25. Likely have a quantity discount.
That Reading coal is white/low ash but doesn't have the heat output of the Blashak.
Hope to have some sort of coal bin or storage set up next year and start bulk deliveries.
Been lurking here for a couple years and thank all for a great sorce of coal burning informaton and wisdom.