I purchased Sleepguard after being diagnosed with sleep apnoea (30 stops/hr up to 30 secs each). The specialist suggested either an oxygen mask which would have been hugely intrusive and lifestyle changing, or firstly to try a medical gumshield to see whether that was enough. I'm really glad I went down this route.
The item looks like a sports gum shield, soft, lightweight and the instructions are very easy to follow. You immerse it in very hot water for 30 seconds then into your mouth, champing down with your incisors (front teeth) aligned. The Sleepguard moulds to your teeth and gum profile and sets firmly after fifteen seconds or so; put into your mouth just before going to sleep, the net effect is to bring your jaw forward a little - it is this (mandibular advancement) which stops you snoring.
When you begin to use this device, it takes a week or two to get used to it, but it is not actually uncomfortable and I find now that I'm no longer aware of it. It also makes you breathe through your nose, so it is important to check that your airways are clear before retiring.
The device works, and very effectively too - it may also ensure that your partner enjoys an undisturbed sleep. It prevents snoring and possibly sleep apnoea, and consequently will enable a better sleep experience. In the nine months that I have used this, I can report that now, I only very rarely feel tired during the day and am generally far more alert. I clean mine every morning - when brushing my teeth, I brush this too using a little toothpaste and water.
Pros and cons: pros as above and well, there aren't really any cons. Excellent value for money.