Digital swing-away presses are by far the dominant choice for awards retailers. This is because they often want to sublimate more than just shirts and thin materials. Swing-away presses ensure even pressure, even onto thicker products like tiles and plaques, by pressing evenly in a cylinder/piston style of action. Clamshell presses pressing at an angle will not accommodate thicker materials evenly.
It is also important to note that many swing-away presses are limited in pressure setting range, so make sure the press is capable of pressing materials up to 2″ thick to guarantee fitting thick materials and special padding required.