I commute on the same city pair as the #2 guy at Airways. There have been times I've beaten him although that is tough as he is a block holder and I am a reserve. Anyway, the US jumpseat system is great solely because of the planning aspect of it. I have done it the other way for years and the stress is tenfold. This way I know if I book it I'm good to go.
Seniority is not everything and is way over blown in the industry. The 23 year old new hire needs to be able to get to work just as much as the 30 year widebody CA. Probably more so seeing as he's on probation.
It's an awesome system too bad we can't book the commuter jumpseats (huge can of worms!!).