>	- what are the upgrade issues for people running bind8 ?

	see doc/misc/migration in BIND9 tar.gz.  bind9 is pickier to some of
	the zone file parameters.

>	- what other pros / cons are there of bind9 over 8 ?

	pros: IPv6 support
	cons: performance drawback (lower query-per-sec, but it is improving)
	cons: unneeded A6 query issued (9.3.x should fix it)

	there are other items documented in doc/misc/migration.

itojun