I picked up a Big Buddy portable propane heater a couple of weeks ago, but only now have had a morning cool enough to give it a test. I'm impressed, got my family room toasty warm in rapid order.
Plan is to take along one or both these heaters on cold mornings when our daughter has fall softball tournaments. But they were primarily purchased to be home heating backups (oxygen sensor allows them to be used indoors) during power outages, and I might even use one in the basement or garage while working on projects this winter.
Only downside is the propane bottles have become rather pricey, often retailing for three dollars or more at stores. Bright side, I've seen valves available that allow the disposable bottles to be refilled (for personal use only) from a 20 gallon tank. I also picked up an adapter that allows the Buddies to be fueled directly by a 20 gallon tank in outdoor settings.
Now that the heaters check out, what's a reasonable and practical number of one-pound propane bottles to keep on hand? We also have a propane camp stove using the same fuel. Nine bottles fit nicely in a standard milk crate.