Jon...

It is definitely ready for prime time if you're willing to work around the missing tools and lack of DTS.  Short of those problems, everything was fine.  You will find the linked servers to anything other than another SQL Server to be very flaky.  I use it to support a BI application using 64bit Analysis Services and it hasn't gone down yet.  I am supporting over a terabyte of data and multiple cubes over 50gb in size each as well as basket analysis.  All this running and you can't put a dent in the machine.  This is truly a transition point until Yukon is available, and then it's just an upgrade!

Scott