Personally, I don't like it much.
My toothbar is held on with two bolts. Goes on and off in a couple minutes. There are times when you don't want the tooth bar on. It would be a pain to take one off that has that many bolts. I would also imagine that the nuts/threads on the bottom might get dinged up and that would make matters worse if you wanted to take it off.
The one I got slips over the bottom lip, totally covering the lip on the top and bottom, and has replacable teeth as well. It is very strong. It did cost almost double the one that is on ebay though. But I think it is money well spent. Yesterday it helped move about 100 tons of fill, dirt with some broken concrete in it...
Here is a pic of a toothbar at work. I posted it here somewhere else, but forget where at the moment...
A well made toothbar is probably worth $300 in my opinion. Glad I bought a good one! Money well spent...