I'd go for tech at a first glance, because it's grounded in rules that impose limitations, making its creation and use feel more of an achievement. However, magic has its appeal, especially when it's unpredictable or unknown, adding a quality of adrenaline to its use that sci-fi tech can't reach without breaking its own laws. So overall, tech if it has opportunities for advancement and alterations, and magic if it is alien in some form.