As mentioned in numerous threads before, there are two schools of thought on tropical diving and plates. Some of us dislike weight belts and/or perceive a benefit from the steel plate being located right up against one's back, closer to the center of buoyancy than lead on a belt. I take my steel plate to Cozumel and other tropical destinations. With a 3 mm wetsuit, aluminum 80 tank, and steel plate, I am perfectly weighted with no additional lead at all. The difference in my luggage weight between the choice of steel or aluminum is all of 4 lbs. or so--not a big deal for me. I don't take a lot of stuff when I travel to tropical dive destinations, I don't buy souvenirs, etc., so my luggage weighs in at under 50 lbs. even with a steel plate in there. For those who travel with a lot of stuff and don't perceive any disadvantages of weight belts, aluminum (or kydex) is indeed one way to reduce luggage weight by 4 lbs. or so.