Pedals don't make much of a difference in ride, no. You can use SPD's on a road bike, and the cleats either fit or you can buy an adapter plate for your road shoes (for example, you'll need an adapter plate for Sidi, but others like Specialized have the two-hole SPD cleat pattern). If you stick with it (or need more float than SPD's provide due to knee soreness) you might want to think about road pedals.