If it were my choice and I could find it within my budget I would go with Juki. Not that Janome doesn't make good machines - they do - however, Juki's base is industrial machines, that knowledge and technology transfers over to their home machines. They are strong, capable machines that will last a very long time.
I have plenty of regular sewing machines but I am lusting after a Juki serger.
Enjoy with whichever you choose. Neither is a bad machine.