Definitely Not Ready for Release
They've got a lot to fix before this OS will be ready for mainstream usage. Here's the issues I've run into so far using beta 6:
1) Syncing is hit or miss - corded yields album art syncing and unsyncing itself randomly
2) Wifi Syncing is a disaster - half the time iTunes doesn't even recognize the phone, and when it finally does, it hangs at a "waiting for changes to reconcile" message at the last step and I have to force kill everything just to stop the syncing - it worked with the sync a podcast trick someone posted elsewhere -- ONCE - after that, wireless syncing locks up every time (rebooting both mac and phone)
3) Changes to notifications requires a reboot to make any of the changes effective
Everyone is convinced that the final release is right around the corner, but I can say that if they release this thing without putting out another beta to address the flaws it has, they're looking at having a slew of pissed off users. There's huge potential with this release, but its extremely aggravating that through 6 betas they still have yet to address these rather large issues.