The drawbar on my YM2000 looks like the one Aaron posted, but some of the other Yanmar stuff I've got has a rectangular bar.
One nice thing about a 3 point mounted drawbar is the ease of attaching to a trailer for quick moves: Back up under the hitch, lift the 3 point, and drive away.
The disadvantage is that with heavy loads on the 3 point, both in tongue weight and in force to pull the load is that it tends to make the tractor lift the front more easily than the same load on the drawbar. The drawbar's position and height mean that the tractor has much less tendency (To the point of near impossibility) to tip over backward. As well, the drawbar usually will hit the ground before the tractor can tip over to the rear, which should make it nearly impossible to flip. However, operating uphill or under extreme situations makes about anything possible.
The 3 point linkage, in contrast, doesn't have the same rigidity to combat a rollover to the rear, and gives whatever load is on back a mechanical advantage to let the tractor walk the front end up. That trait also gives you more traction, though, which is why it's a popular thing to pull from an implement or the 3 point, since it just works better.
I wouldn't be worried about the sheer weight you're putting on the 3 point hitch if you go that route. My manuals list much lower loads permissible on the drawbar than the 3 point is rated to lift. For instance, a 600 lb load is a quite heavy trailer hitch, but is only about half what the 3 point lift can do on a YM2000/2002 etc. It's about double what the drawbar load should be, though.