This is the best "Overall" best Night guard for TMJ Symptoms available. It also protects your teeth from the affects of grinding. The downfalls of this guard is that it won't be the best guard for you if you have a very small mouth, a small arch width of your teeth or a very high palate. Generally it will work for about 80% of the population. Also, if you have an end to end bite in the front teeth, it may not work well for you.
The problem is that the alternatives are much worse in many different areas, so my recommendation is to try the SmartGuard first, because it most likely will work better for you.
The surprising symptom that this guard reduces, is the tension headache and even some "migraine" headaches. It seems that the most common symptom relieved as much as jaw pain, is the headache. Statistics show that 82% of headache sufferers will have a 77% reduction in their headaches from wearing this guard.
The SmartGuard is the best one that I've found that you can buy off the Net, and it's a lot cheaper compared to the ones you get from your Dentist.
There are big differences, and you as a Consumer would never know the difference of which one works best unless you tried multiple guards.
Now I have done the work for you. If you're wanting a Night Guard, get this one...
The SmartGuard Night Guard.