The advantages far out-weigh the disadvantages to me. As has been said, you can get better soil breakage, load materials into the bucket easier (ever tried to load a balled up mess of leaves, vines and sticks and have it roll out in front of you?), and pop up small roots to remove saplings etc.
The toothbar usually mounts with only one 1/2 - 1" bolt on each end of the loader, but some have other methods such as bolting along the cutting edge which is not preferable in my book.
The only disadvantages are that the teeth stick out further than the cutting edge, so extra care in turning close to fences, houses, cars, etc. most be taken, and one has to be careful not to walk into them as they HURT!
The bar can come off very quickly when you want to use the cutting edge for smooth backdragging, but that's not always necessary as was said earlier.
Check out
www.markhamwelding.com as many members have ordered their toothbars and have been very satisfied. Also, if you have a Woods Equipment dealer near you, they can order one for you. You'll need to measure the inside width of your loader bucket just behind the cutting edge and have that available when ordering. If you have a bolt on, not a weld on cutting edge, you may have to order from someone like Woods who offers a heavy duty toothbar for bolt on edges. I understand the Markham toothbars are only for welded cutting edges.
If you enter toothbar into
www.google.com , you may come up with even more suppliers of toothbars. You may even go to a local welding shop and have them make one for you. There are numerous pictures of toothbars on TBN, just go to the top of the page and click on search, choose all forums, enter the word toothbar, entire phrase, and use the drop down menu and choose newer than one year, and you'll get plenty on toothbars.
You can right click any of the pictures and choose "save image as" and save it to your computer so that you can show it to a fabricator/welder to make one for you.
John