I got the 70 lbs. title legged grappling dummy.
It was on sale at the time I think I paid somewhere around $150 at first I was worried that I was wasting my money but nothing could be further from the truth. The grappling dummy is a great investment for someone serious about throws.
The cool thing about it is that you can work on whatever throw you want to as much as you want to. When I first got it I used to spend almost half an hour straight throwing it around. I used to try every throw I knew and some new ones, each time doing a different throw to help train going into any throw I wanted to. Then later when I started to see my mistakes more I started just focussing on one or two throws a day for one week for 10 minutes.
Now I'll also do more of a cardio workout with the dummy for example doing a throw like a pick-up as fast as I can and as many as I can for 5 minutes straight. Afterwords you have to put your hand on your heart to make sure you're not having a heart attack!
I also work my gripping sequence on it.
You can also do pinning drills with it, and of couse armbars. But since I do those a few times a week at the gym I mostly focus on my throwing technique because there's not too many people who are going to allow you to shoulder throw them 30 times in a row at full speed and power.
The only drawback is some throws you have to slightly change to work well on the dummy. For example I got the legged dummy so I could work on ou-ochi gari or inner hooking, but even when I do hook it doesn't really go down fast because the weight switches legs slightly and the throw comes off kind of sloppy (when I do it anyway) so now I'll do the inner hooking by sweeping both the legs at once as if it were one leg.
But overall the more I use it the more I am able to use it the same way I'd throw anyone else. I took JW and his students advice and went with the lightest weight for Title, because the problem with the heavy weights is that everytime you throw it you have to pick it up and besides when you do a throw right your opponent doesn't feel heavy anyway. Not to mention these dummy's have dead weight so a 70 pounder feels more like 150. So I figured why waste your energy on picking up a heavy dummy when I could use for that energy for my throws.
I also only throw in on a mat to keep it from falling apart. I read up on these and it seems that if you push it too much these do eventually break down. So I treat mine like a human.
Hope this helps.
Let me know how it goes.
Good times,
Greg