I guess you'll have to look for expos and shows? That's where I played with the Bernina Q20 recently. I don't think I've every played on the Janome LA, but I'd like to. My main machine now is a Janome and I like it quite a bit.
That's also part of why I figure I'll make my decision sometime close after PIQF - I think just about every LA maker shows up there so I should be able to talk to someone about and test-drive any machine I'm seriously considering at that point. And maybe even get a deal!
