check out the Long Arm University website--when I was looking she had a great list of features so that you had a way to compare different models. also she lists used machines so you get an idea of price. also check the website of your nearest dealers for each as they may have used machines, too.
I know you are thinking about dealer closeness, but I have to be frank--long arms are so honking big/heavy that good tech support via phone is what is most important. My dealer is 3.5 hrs away; I've had the tech actually at my house one time over a year ago for a general check-up, had a local man whose wife is a Gammill rep (she teaches classes at shows for them) come and do a check-up once--otherwise everything has been via the tech support talking me through issues. Long armers either have a "mechanic" in the house or we become pretty adept at working on our machines! Also there is a long arm for sale (not sure of actual name) page on Face Book. Good luck--I love quilting and enjoy it even more than piecing.
And once you get it try to get to some big shows where there are classes for long arming--I've been fortunate to take from Dusty Farrell, Kim Brunner, Sue Heinz, Angela Walters, Jamie Wallen and Pat Barry--all very good. You might also check to see if there is a regional machine quilters guild in your area (you don't say were you live)--we have one in KC area and meet every other month and it's been a big help for me.