[10.3] Should I use "pause" or "go to the frame" to stay in one place?

It depends on what's going on while you've stopped. Using pause stops the playback head, stalling any ongoing animation (whether score-based or managed via Lingo) and any other periodic activity. However, events are still processed, so all your buttons and event handlers will continue to work. This is ideal if, for example, you just want to do nothing until the user presses a button, chooses a menu option, or whatever.

If, however, you have other things going on -- for instance, if you are using some kind of animated buttons, or have background music loops which change at certain times -- you'll need to use go to the frame (or something similar such as go to marker(0)). Keeping the movie running on the spot allows your scripts to do things which are not based on user events, such as swapping castmembers onstage or checking whether a sound is still playing. These kind of periodic tasks are usually based on the frame movement events (exitFrame, stepFrame etc) which are suspended while the movie is paused.