LUMOback

Lumo Back has since been replaced with Lumo Lift, so I'll address that instead. 

It's a good tool when used properly. The problem is using it without any education. If you just put it on your shirt and go, then it might successfully remind you to "sit up straight" but are you swaying your back in the process? Are you jutting out your ribcage? If so, you may be creating more problems than solutions. 

The same way you don't know how to build a house because someone hands you a hammer, or know how to back up a car because there's a backup camera, tools are only helpful if you're educated about how to use them. In the posture desert that we live in, the education is a bigger and more important piece of the puzzle than the tools.