The jet air threaders are nice. BUT - The Evolve or whatever they call it now has a wide foot since it will switch from serging to coverstitch. The Imagine has a much smaller foot and will do small items far better. You can always get a separate cover stitch. Janome has one, so does Babylock. Probably a few more. The Babylock CS will use the Evolve special feet.
If you can, go try them out.