Disklavier

I am looking to get an upright piano for my family and have come 
accross a used MX100-II for $5500 from a private party.  I went to a 
local Yamaha store to see the new models and found the salesman lied 
about the models to clear an MPX1 (?) off the floor for $13K and said 
the Mark III vertical would be unavailable until July 2003.  It looks 
like it was introduced last year!  I could afford a new piano but 
like to get a good value and am not certain whether it makes sense to 
buy a $15000 new DU1A when I can get a good quality used MX100-II for 
little more than a third the price.  Of all the features I see on the 
DU1A, the most interesting is the "silent feature" so my kids could 
practice and I would get some peace and quiet when they are starting 
out.  Also my wife could practice after the kids are sleeping.  The 
salesman told me the mute rail (felt muffler) was included in all u1 
pianos and probabaly adequate.  Has anyone bought the DU1A and if I 
wanted to go that route, what would be a target price for sale?  Any 
other thoughts from owners of these models or other disklavier 
afficionados?