*Written from personal experience from this point in time. If necessary, updates will be written.
The Good:
This item is an enhancement to your daily carry flashlight. As a description, I will simply call it a round index finger ring that attaches to the button portion of your flashlight. I have owned and carried a flashlight with this addition for nearly a year now.
The Thyrm Switchback offers generous room for your finger and indexes the flashlight the same way in the hand every time. It allows a more secure grip on the flashlight and allows an easier draw from the pocket or pouch. It also allows the shooter to maintain the flashlight in the hand when performing a reload.
The Bad:
While the Switchback offers a pocket clip attached (large flashlight models only) it is designed to be carried in the front pocket, which may not work for some. The method of using the flashlight in a 2 handed grip has a steep training curve, and does not seem to be a viable method for my use. The Switchback piece itself can have a tendency to rotate out and print if carried in a pouch on the belt. Finally, the rotation of the part on the flashlight can be overcome with some rubberized tape on the flashlight cap, but is annoying.
The Takeaway:
The downsides to this part has not made me quit carrying this part of my flashlight and it has been a very useful tool for what I need out of it.
Always be safe and remember the 4 gun safety rules!