The Gel: Pro: The gel itself is nice. I have seen some results with it. Zero sensitivity. I'm not sure if it's any more powerful than other brands. It seems similar if not identical to other brands gels, but I have to dig deeper for that info. Con: The syringe didn't come with something to easily dispense the gel. Unless you are very careful, way more than you anticipate will be pushed out of the syringe, which is so wasteful especially considering the cost The Mouthpiece/Light: Pro: I love that I can plug it into my phone! I've tried battery ones before, but it felt too heavy to hold for 30 minutesjust by my teeth. This version is light! I also like that it's such a strong light. This was what sold me in the first place, because they said the strength of the light makes the difference in the effectiveness of the gel Con: This, by far, was my biggest issue. I did reach out to staff about it, but was just told they sampled mouth pieces and this is an average mouth size. When I say that my jaw could not fit in this mouthpiece, its an understatement. The directions say you can paint the gel on or apply it to the front of the mouth piece and press it against your teeth. My teeth, in no way, pressed against this mouth piece! It is incredibly narrow I am surprised anyone can use it. I have a normal mouth shape --no major over bite or underbite, no wonky teeth that would prevent my teeth from fitting a normal mouth piece (and I have not had an issue with any other brand's mouth piece). I had to cut out the entire middle portion of the mouthpiece to just comfortably hold it up with my hand to get through a session because it hurt so bad. Yep... this is how i have to use the product... holding it for 30 minutes with my hand so my mouth doesn't have added stress of trying to fit in something 3 sizes too small. Before I cut it, it felt like it was trying to move my teeth inward (imagine trying to walk but pressing your knees together and inward)... 100% unnatural. As I said, I reached out to staff. The response I got was polite, but offered no solutions. I asked of they had advice on making it more comfortable... nothing. They just said in their research this is an average mouth. I have no idea how. I was expecting a little more empathy and some tips as to how I could make it a better experience in an effort to show they care. Again, the response I got was in no way rude, and the reply was fairly quick! They did apologize for my experience, but they didnt seem too concerned with my issue. Disappointed overall. I will finish the gels, but regardless of how white my teeth get it's a painful and uncomfortable experience every session. I wish the mouthpiece was moreade from a more flexible material and not so rigid. I wish it could be adjusted (perhaps another size option for more normal mouth structures). I wish there were tips to make it a more positive experience. I'm more than willing to find ways to make things work, because no matter what you buy it won't be a perfect fit for you. Aside from the mouth piece, I like the brand and its overall concept of teeth whitening. There was a reason i chose Novashine over the myriad of other brands available. Still trying to trouble shoot it and make it work. But 3/5 starts because of the pain!