MilesBuzz! - Best FF Program for Elite and travelling companion?

I have not been an elite for a few years and when I was a few years back I always travelled by myself. I'm planning to make a few award travels next year (Dom and INT) with a non-elite companion (options would be UA, NW, or US).
I will be makin enough trips in the second half of this year to achieve at least mid-tier status on the carrier of my choice. Which of the above (if any) would be better as far as perks (check-in, lounge, UGs, etc.) for both myself AND a companion?

Thanks
Mike

Anybody?

Gleff, did you indicate to me that you had done some comparing at one point?

If so, did you find anything worth passing on?

Mike