vibratory polishing is the cat's rear when done by a pro and HIGHLY recommended. it's usually superior to a job done by hand because it polishes every nook and cranny hand polishing can't reach. the biggest downside is removing texture is difficult this way. it just slightly reduces it and polishes the texture and not completely remove it.

whatever you i would suggest using a sealer on the finished product.
if not sealed polished aluminum will be unpolished in a short time, depending on how picky you are.
google polished aluminum sealer for products, there are a LOT of them on the market.