They are quite smooth but can get very expensive, and may not be as versatile. More important than the machine itself though, is your ability to get help when you need it. Owner's manuals usually are of little help and these days and often aren't even translated properly into readable English. I would recommend any of the Sailrite machines and more importantly, the company that backs them up. It will still sew through magazines and can then be quickly adjusted to sew two layers of spinnaker nylon.
Most lofts use bigger, faster machines with more room under the arm.
They are quite smooth but can get very expensive, and may not be as versatile. Owner's manuals usually are of little help and these days and often aren't even translated properly into readable English. I would recommend any of the Sailrite machines and more importantly, the company that backs them up.