i own two janome machines, one of which is the MC6600P. i absolutely love both of them and have never regretted the selections. however, when i was shopping around before buying each of them the choices narrowed down to the janomes and the equivalent vikings models. in terms of features and reputation they were equal. i chose the janomes because the dealer is "only" an hour away and sells at fabulous prices compared to the other sources i checked. the nearest viking dealer is a four hour drive.
who cares what the LQS salesperson thinks or says? she's just trying to convince you to buy what she wants to sell. she is not objective. frankly, i think her sales tactics are tacky and unethical.
you have personally tested both brands. the viking worked best for you. you already know you like it best.
get the viking.