Well I have an automatic in '80 Vanagon.  It works pretty good so far.  It 
has 110K miles on it and still shifts really smooth.  The only draw back 
that I can see is the acceleration and the power.  It seems that the tranny 
uses up some of the little power there is in the torque converter.  It also 
doesn't accelerate quite as fast as I could in my '71 bus w/stick.

When I am going down the highway and I hit a BIG hill i usually have to down 
shift the transmission  because the  transmission waits too long before it 
will downshift to go up the hill.

I have driven in DC traffic and YES an automatic is a necessity in my book.  
But hopefully you wouldn't be driving your nice van all over DC.