When just grabbing them and in use, they are very different animals in my opinion. The Ontarios are typically heavier and somewhat thicker, slower to swing, but pack a nastier hit. The tram swings faster, is lighter, and slices very well. They are both great machetes from what I can tell and both take and keep a great edge. The Tram appears to be much better for typical "jungle-y" green veg/shrub/soft tree/grass cutting, where the Ontario will be better suited for heavier chopping tasks and harder wood. If I'm walking all day in the bushes I'll take the Tram, but if I have some heavier tasks/shorter walks/hardwood cutting needs I would certainly grab the Ontario. Both need work before they're ready to work. The Ontario needs the handle trimmed and shaped unless you have bear claws for hands, and will need a good sharpening. The Tramontina needs some trimming, sanding, and oiling of the handle to get it comfortable and feeling right, and needs a lot of work to the edge to get it where you want it. Both file/sharpen easitly, but still keep the edge well until you bury it in the dirt or a rock.
I have no experience with broken machetes other than one breaking in half while a friend used it...it was a rusty woods find so the blade was in bad shape. And I don't have a plastic handled Tram, so I can't say about the tang. The wood handle version is full tang, but doesn't appear to be full-width (about half or 2/3 the width of the handle from the spine down).