While yes, the 17th has more content and users, here.os a quote from and old Fandom user that I particularly agree with
"I always thought that the Coppermind was kind of disorganized, hard to navigate, and frankly, looked like it was built in the early 2000s. I personally think its annoying how they will have multiple pages giving the same information when it could all be neatly kept into one very informative article. "
Fandom has more up-to-date software, is more user friendly, and the developers are much closer, if I spot a technical problem all I need to do is write an email, and it will be fixed within a day. If I have a question about anything whatsoever technical, again all I need to do is write an email, and get a response within the day. And more along the lines of user friendly: while it is also easier to edit, contact developers, and post messages and fourums than the 17th; on Fandom there is many more customization options, with personal css and is, as well as advanced preferences. The things availible with Fandom are much more multitideinois than on the 17th.