As good as BikeForums C&V is, it isn't everything and it is driven by the knowledge and opinions of the people who are here, with all our goods and bads. Other sites are similarly only as good as their contributors. If all the participants are the same, two sites might be of equal quality. But they aren't the same! I check out three other C&V sites, and while there is some overlap, there are members on each one that are not on any others. In some cases, better experts are elsewhere.
So I say, bring on the C&V alternatives, so we can learn from a larger knowledge pool.