I think Flying Blue is fine but the posts above pretty much summarise it well.
If your flights are mostly domestic, it's hard. But really, US based credit cards make it easy to earn points to transfer for award tickets anyway. And it depends on needs.
Flying internationally is not hard within Europe; one hour flights from Germany to France or NL net 5XP in Y and 15 in J and if one's travel patterns line up, it can work out without too much effort. And I am satisfied with my Silver status. The checked bag allowance and priority check-in (and sort of boarding) are suffisant for me.........
As for dynamic award pricing, don't the big 3 US airlines do it too ?