I just wanted to share my experience of using a screw-down press like the one pictured above with anyone frustrated with or considering upgrading the old plunger style press we all start out with. Having used the plunger press for a few months, I can safely say that this upgrade makes a HUGE difference in the quality of fit and time it takes to set the crystal correctly.
Obviously, whose crystal you're using (more on that in a future post) also makes a big difference but if you're planning on doing more than a few mods, spring for the more expensive press. It allows you to apply pressure more gradually and evenly while allowing you to view your work more closely. All in all, these presses provide more control and thus, precision to your work (as well as fewer headaches). Don't think twice about getting one.