not bashing butane, but propane is easier to get...
I don't know much about butane, other than it has similar property's to propane. I have only seen butane bottles at an Asian store and at a restaurant supply store.
Propane bottles are at Walmart, Target, Lowes, Home Depot, Menards, CVS, Walgreens, Publix, & any sporting goods store. You can use the propane bottle for lanterns, camp stoves, camp ovens, heaters, coffee makers, & crock pots. Plus, with adapters, a 1 lb bottle can be used on your home grill, to power an RV fridge, and to refill from a 20 lb BBQ tank. Plus, any of the appliances noted above can be used from a 20 lb BBQ tank with an adapter.
The 1 lb propane bottle is more versatile and easier to get and refill than it's butane cousin.