I have ceramic on my upper six, it looks like I am wearing a retainer and most times, people don't even know I have braces. A co-worker asked me a few weeks ago what happened to my braces...she thought I had them off for some reason.
My ortho placed the metals low on my bottom teeth and you can not see the brackets when I speak so it isn't so bad. My ortho does this combination on adults, he uses self litigating brackets so there is no worry about staining. I asked him why not just do all metal and he said I wouldn't like it. He was right, like someone else said, I am not confident enough to go all metal. Plus, the self litigating metals are simply a full metal square, if you will. There is no spaces, just metal and in my opinion they look different than metals that have ligs. I would have prefered metal brackets that need ligs. I open my mouth and I see too much metal. I hate the metals but luckily, you can't really see them.
It really is a personal preference and your ortho will do what you ask for. Whether you use metal or ceramic brackets, will not have any effect on your treatment plan.
Ceramic/metal brackets will look different depending on what brand is used, my suggestion is while you are there for your consult, ask to see some of the patients. This way you can see what they have and maybe ask their opinion. It really makes a difference when you see what the actual brackets your ortho uses, look like on real people. I think of all the pictures on this website, I have seen one or two people who have the same ceramic brackets on top, like I do. So, just from looking at photos on a webpage, you may not get a good idea of what they could look like.
If it is anything like my ortho's office, there will be plenty of human examples for you to look at.
Another thing I like about my ceramics, is that I get a better idea of what my teeth look like as they are changing, with the metals I can't really tell.
As for the toothpaste, the cinnamon might just be too harsh for you. I would stop using it if it continues to give you problems. I have problems with Listerine mouthwash sometimes so I use ACT regularly now. Ask your ortho if you should be using whitening while in braces, some people have been told not to use whitening toothpaste while some have been told it doesn't make a difference.
Good luck and keep us posted.