I don't have any of the 3 machines you listed, but I can give you my two cents! :D
Here is some info on it:
http://janome.com/index.cfm/Machines...ing/Sewist_500
It looks like a basic sewing machine. Is that what you're looking for? Have you decided what features you need to have and what features would be nice-to-have? I need to have a needle threader because I can't see the eye of a needle any more! :D So that's one feature I need to have in a sewing machine. I also like having a bobbin indicator for when the bobbin gets low. I don't use a lot of decorative stitches, so I wouldn't be looking for those in a new sewing machines.
Those are just a few of the things you will want to think about before buying a new machine.
Good luck!