This year, "real" wood was not obtainable at a decent price, so I tried
http://www.pelletsdirect.com/Envi Block & Logs.htm
And used the Envi-8s
Good:
delivered on time, as promised.
6-packs of blocks, not light, but easy to carry.
Wrapped pallets take up minimal space.
Lights very easily.
Very controllable, easy to keep stove on a low burn. My stove is relatively airtight, but 30+years old. No catalyst.
Good burn time. Four blocks @~10 PM; four blocks @~5AM Stove still nice and warm, keeps family room from getting cold. Add blocks @~ 4PM (return home from work), this time with more air. Gets it going nice. Figure ~6 blocks till bedtime. If it's really cold, a couple more, to compensate.
Downsides:
EXTREMELY sensitive to wet!!!!! When the delivery arrived, we took a good supply of blocks in. Unfortunately, several 6-packs were damaged in our enthusiasm. Two days later, it rained. Damn things swelled up like the sponges you put in water, dry, that then expand. Expanding 6-packs damaged others. I salvaged a bunch of them, but the expanded ones did not have the same burn time (due to less density),and held water a bit. Keep the heavily-wrapped pallets intact as long as you can, and tarp the crap out of them, if you don't have inside storage.
Expensive. Cost is ~300/pallet. One pallet in theory equals one cord. If you can get wood for <$250, that is likely a better deal. I was not able to, this past season, so......
Summary:
As to heat value.....From October to mid-march, I used 2 pallets, just opened the third this past week. Might not have had to open it, had I not lost some to wetness. So, I'd say that the heat equivalent is about right. My stove tends to run from October, to the end of March. From min-November to the end of March, it's pretty much just one fire. Since I'd generally burn ~2 cords of wood, that's about right. Since the blocks are very dry, there's no heat needed to "boil out" the water in a piece of wood. More efficient, minimal smoke.
So.....it costs about $5/day in my situation. It helps to cut down the furnace's operating time, a bit.
It all comes down to cost. If I can score cheap tree chunks, I'll go with that; if not, more of these.