I belong to about a dozen.
And yes, the miles are important.
If they don't have a plan..I avoid those carriers as much as I can.
My biggest balances are on my British Airways Gold card which also has my American Airlines miles on them. About 75% of my travel is with those carriers.
I travel in biz class most the time since my company pays...so I end up with about four or five free Business Class roundtrip tickets free a year. With BA,AA, and QN..there is no where in the world you can't go!
Also, they give you a lot of free upgrades...unfortunately, it's from Economy to Biz---not to F Class.