I didn't test drive the Janome, but I love my Bernina. Bought it from the dealer, but it was a trade in. I will never part with it. I ride her hard and put her up wet and she is ready to go everytime. Not a minutes trouble out of it. I think the Bernina has a more complete offering of feet (of course they are expensive) as well.
I think that you should test drive and form your own opinion based on YOUR needs. You'll be happier that way-