No. I don't need ISO's at all during development. 'rsync'ing to a localserver and installing via net from there is cheap, fast and reliable.
This is not my opinion. Some problems are only found with a fresh install or an upgrade of a previous stable distribution.
and lets not forget the problems with
1 time is money | data is more important than money
2 not if you have sub megabit access ON THE MACHINE YOU ARE UPGRADING
3 and how many bugs have been around the network install? (total and just the 9.* series) And what if the bug is in the cdrom installer?