I'm active on SO and got some reputation there, but only come to meta if I find a bug or really badly want a feature. I use the search and find the exact same feature request I would ask for, but can't vote it up, because I'd need some reputation on meta. Normally, I'm just annoyed and go back to SO and live with it.
In my opinion, it would be helpful to give users from SO, SF or SU there highest reputation on meta, so they could use all the features and one would see, they got a lot points and know the platform well.
(Maybe I get some rep. through this question and can vote on the "someone also commented on a question you commented on"-feature)