Hi Dave,
I used to think that front and rear height adjustments accomplished the same thing as far as pitching the bike forward or back, and it does to a point but not entirely. So, what follows is probably an over simplification, but here we go...
Say you want to quicken handling; If you drop the front end (slide fork tubes up in clamps and make the triples closer to the ground), you reduce trail, steepen steering head, shorten wheelbase, reduce ground clearance and REDUCE swingarm angle.
So, in contrast, raising the rear to pitch the bike forward, the effects of steering head angle, and trail are the same, but you are raising ground clearance and INCREASING the swingarm angle.
With dropping the front, the swingarm angle changes are slight, but with raising the rear, they can be pronounced.
Swingarm angle is related to the anti squat tendencies of the bike and can have a pronounced effect on how well the bike finishes the corner (as does rake and trail)
So, if you know what handling changes you want with steering head angle and trail, you can decide which end to use based on desired swingarm angle (increase or decrease), and ground clearance (making the bike taller or shorter).
Hope this helps.
-Sean