Frank, it's not a big difference. The half lug will balance a bit better (as far as center of gravity being towards butt or muzzle), while the full lug will soak up recoil/flip a bit better.
If you get a chance to shoot them first, I wouldn't overlook a 6" barrel. Makes the gun a bit heavier on the end of the hand, but you probably won't shoot 500 rounds per session anyway. The extra barrel length will give another increment in recoil/flip for followup shots, as well as precision of using the sights.
In .357Magnum, I have shot 4" and 6" full lugs, as well as 5" half lug, all in the same session, with the same ammo. All were ok. The 4" would be the most comfortable carry, and offer possible concealed carry. The 5" half lug had the best balance. The 6" full lug had the best practical accuracy and shot to shot recovery.