patricej

any janome dealer is expected to do warranty repair regardless of where the machine was purchased.
this was confirmed for me, in person, by a company representative.
they might not want to, but if you insist they call the company they will find out they should.

one dealer would not be required to provide extras for free, such as routine service and maintenance, if the machine was purchased elsewhere. however, only a dummy would turn down a chance to provide those services for their standard fee just because the machine was not purchased in their shop.

figure out how far you are willing to drive for service and repairs.
the compare prices among every dealer you can find within that distance.
make sure they know you are comparing so they'll be more likely to offer you the best deal they can afford.

p.s. i absolutely love my 8900. i got it for "a song". i went to a major quilt show and bought one the machines they'd used for classes during the show. those machines come out of the box for the classes, so have only a few hours of well supervised use. but most dealers will sell them as used - deep discount - so they don't have to take them back to the shop. the only catch was that i had to wait until the last day of the show to pick it up.