Hhmm...those are some pretty decent prices for those monitors.  Personally, I like the Viewsonic monitors.  Although I like the Sony one also.  I was able to get a 22" Viewsonic for around the price of the PF790.  Of course, that's if you don't mind going on Ebay and bidding on your monitor.  All in all though, I'd recommend the Viewsonic one.