If given the choice for Janomes, I'd do the 350e if you can get it for a good price. That was my very first embroidery machine.. .then I got hoop envy and sold it, got a Janome MB4 which I hated, sold it, got a Brother 4500d, sold that and downsized to a Brother 770 which is kind of going full circle I know...
Is there a reason you are set on the 300 instead of the 350 or the Brother 770? I think you'd like the options that are available on them and not on the 300.