I think you are most likley talking about trick drums. If you have never heard them try to find a dealer close to you and have a listen. Very uniqe sounding drums. Also VERY EXPENSIVE. As we both know drum material is a personel preferance so you may perfure aluminum over wood and some else prefure maple over Birch. It's all about " your sound". You can get some KILLER finishes on the aluminum drums.
i think that wood shells bring more warmth and resonance, yet aluminum shells bring a bright and poppy sound that cuts through the mix. i think aluminum would be good in a rock setting, and wood for probably a jazz setting.