5) Is there a advantage to having a lower AS number?
No.
Some network operators measure the size of their, um, "networks", by the lowness of their primary AS (Scott Marcus-envy). :> ...
Ummm, thanks, I think. :-)
Yes, the lower numbers have sort of a nice cachet to them, and we're certainly happy with ours; however, I would think of it as being more like having a low employee number on your company ID badge. It says more about your longevity and seniority than it does about your rank (or in this case, network size).
- Scott Marcus (CTO, Genuity [AS 1])
wrt longevity & seniority, Genuity is fairly recent. Early AS assignments were signs of early adopters as is the case with some IP space. Given the level of M&A activity, having a low AS number generally means you bought out someone else.