I don't have that model Viking. Mine is a 10 + yr old Platinum model. I love it. Have not had one hour's worth of trouble with it at all. Love the auto tension system. I have sewn sheer curtain fabric to boat cover canvas and never touched a setting. And then go back to quilting cotton.
I do agree with KalamaQuilts...take your own fabric along with a quilt sandwich sample if you do machine quilting or even just to test for sewing on bindings. If you do other types of sewing besides quilting, take some of those samples as well.