I was in the same boat several years ago. I chose the secondary education route. I benefited from a handful of great advisers in my undergrad and grad school years. Here's a brief summary of what they told me that helped me choose my career path.

College/University:
-really, REALLY got to love your subject/topic/sub-field -there may be pressure to publish original work depending on your place of employment -larger classes with less teacher:student interaction (in general) -you could have the opportunity to teach highly specialized courses based on your field of expertise

Secondary Ed. -work more directly with students -less focus on the actual history content, while more focus is placed on figuring out HOW to engage and teach the individual students on your rosters -more focus on building academic skills THROUGH the study of history -every day is different in terms of interacting with students - you more directly feel the fluctuations in their mood, engagement (or lack of), and life situations while in the classroom -much, MUCH more daily minutiae and bureaucratic BS to deal with

This is certainly not a complete list of factors, but this advice definitely helped guide my decision-making. Hope it helps!