Got a Master 50000 btu propane heater for xmas, Are they any good or should i leave it un open and get a biger?

Master heaters are a good choice for portable heat. The 50,000btu model will heat a 1100 square foot building, of course ceiling height and insulation values need to be factored in. They are pretty reliable but they are also noisy and unvented so a small amount of make up air may be required which can be accomplished by cracking open a window.