@SarahGen-- I can't speak for other people, but naproxen was actually easier on my stomach than diclofenac. Diclofenac is a stronger NSAID and can work where naproxen doesn't. But naproxen is safer side-effects wise.
The issue with naproxen is that lower doses are available over the counter and people tend to overuse them. This naturally leads to gastritis and other issues. If used in moderation for short periods of time, naproxen is safe.