You will get mixed reviews but there are many who claim it works. It's different for everyone. Just because it didn't help someone else doesn't mean you shouldn't try it. My advice is to try it and see if it works for you.
As far as type, brand, dosage....
Type is largely up to you. Most will go with oil. It will absorb into your body more quickly than gummies although the gummies (or other edible) will probably last longer in your system. I have had friends claim the cream has worked well for muscle issues, so I would assume it has potential for arthritis as well.
Brand...I would stick to the internet on this one. Gas stations are always a no-go and most of what I have seen in health food stores is not quality. A company that publishes their lab results would be my choice. Also transparency on how they extract the oils. Here is a good example of a company I would try:
Penguin CBD is the #1-rated premium CBD oil brand. Our products are completely THC free, American grown and GMO free.
penguincbd.com
Not sure if you are a veteran/active duty but if so they offer 25% off which is the best I've seen.
Also if you try it and it's not for you, they offer a 30-day no questions asked full refund.
Dosage...it will differ for everyone. There are too many variables that would impact this such as height/weight, gender, metabolism, etc. Most will recommend starting low and working up till you found something that works. I personally would start at about 5mg 3x/day but again, that is me.
Not sure if that helps at all, just my 2cents. I am not affiliated with the above company in any way, nor do i continue to use CBD (I found something else that works for me for my health needs) but they have a blog section with articles that should help answer questions and you could email them as well. I would say it is worth trying for and if it works, great, if not, well you tried. I think many people probably give up too soon.