I have a Jem Platinum, which was the top of the line until the new one came out last month. I take the Jem to all my classes, but for weekend retreats, I lug my heavy Janome.
Maybe some day I will trade the Jem in for the new lightweight machine, but the Jem still works fine and I love it, so I'll keep it a while longer. Go on Janome's website to see both machines.
Since the new machine came out, some people are trading their Jem's in for it, so you may be able to get a 2nd hand Jem at a good price. The Platinum originally sold for $500. They're probably closer to $400 new now, so you can likely get a used one for just a few hundred dollars.
The only negative I have is that it doesn't like extremely thick stuff. I was trying to quilt pot holders using prequilted teflon-type stuff and it was too thick. Otherwise I can do anything on the machine.