Charley most of the saws of the type you are describing and yes I have one are actually a Jig Saw not a scroll saw. While the blade goes up and down in a totally vertical manner it is incapable of using the smaller and thinner blades because of the style of the blade they have to use. The most common design is the parallel arm, in which a motor is attached near the back of the arms and the two arms always remain parallel to each other. The C-arm variant uses a solid "C" shaped arm, with the blade being mounted between the two ends of the "C". The parallel link type, used by Hawk, Excalibur, and DeWalt, has rods in the upper and lower arms that are "pushed" by the motor to move short (about 4 inches – 100 millimetres– long) articulated arms which hold the blade. These are the most common and most of the time use only pinless blades although some do allow for the use of pinned blades as well. Most modern saws now a days are very similar but vary widely in the amount of vibration that the saw produces in use. Generally the more the saw costs the less vibration it produces at all speeds. A good test is the old nickle test. In this test you balance a nickle on its edge on the saws table and then turn on the saw and then speed up the saw if the nickle falls over or is vibrated off the table you will have a good indication of what it would be like when using it.
DW