Well, here's what I learned. Yes, a lot of people use them. However, I found out that I didn't need them as I all had to do was adjust the inner spring inside the bobbin case. Most people don't realize there is an adjustment for that - but it's a tinier screw (mine is located on the front side of the bobbin case). It actually pushes the spring out a little when turned, which puts more pressure on the bobbin, stopping the backlash. That's all the bobbin genies do.
Before I figured that secret out, I purchased a 1" whole punch from the scrapbooking store, punched out parchment paper circles, and then used a regular hole punch to punch the center hole. I then put several in a shot glass with some machine oil. When I used one, I would pull the next oil soaked one up on the edge with tweezers and let it sit there, draining, then when ready, put it in my bobbin case. Worked like a charm!
Once I discovered how to adjust the bobbin, I don't use or buy anything anymore. Most people never know you can adjust the bobbin springs, as it's apparently a well-guarded secret. I sure didn't know - just figured it out by accident! But now, that's what I do. Once you get it right, you never have a problem with backlash again. And if you don't have a problem today, then yours is already adjusted perfectly.
Just works for me :)