Having just gone through two WM6 rom flashes and complete re-syncs in 2 days, I can confirm that syncing of my Outlook data takes about 4.5 hours by Activesync 4.5 and takes less than 45 minutes directly by wireless connection to the Exchange server. So yeah - I'm sticking with wireless for future initial syncs also.

No, your partnerships are borked since you've reflashed. You need to redo them, with all the attendant risks of duplicates.

I've taken to using mail2web live as my sole "partnership" - I leave my outlook alone now ;)