The Ontario 18 inch machete may be the 'go to' blade which I've used most in the wild. I have a few older examples with reprofiled blades which cut amazingly well. Of course, over the years I've tried a variety of shapes and sizes and the 18 inch represents the best length for optimal power chopping. The machete is splendid tool that covers a multitude of applications in the field: it is a classic. I have found myself using it in the woods when my Basic 9 seemed too short for the task at hand. The greater reach of the machete makes it a very useful tool for a variety of situations. Most types will hold a good edge and are fairly easy to sharpen with a file. Be sure that the handle is free of imperfections that might irritate your hand when you swing it.
I found a 'Black Prince' at a garage sale many years ago in Boston. It had been used and abused when I picked it up, but the blade had some spring to it and I took her home and cleaned the blade. That 18 inch knife has a thin edge and has held up to anything I've dished out. I've loaned it out numerous times. The high carbon blade has stained but it cuts like a house on fire, easily ranking up ther with the very best 'choppers' I've ever had. No, it isn't pretty, but it works, time after time on hardwood, pine and any other greenery I am likely to encounter.
Some folks like the Tramontina brand. Whatever you select, be sure to get a proper edge on your knife and pay attention when you use it. The machete is a great tool and even a better weapon but will cut you if you make an error.