If doing a lot of off road I would choose the sintered metallic but as you are commuting I would go for the ceramic. Myself and my missus do a lot of bike touring on the mtb's and on some very very steep roads in Central America we chewed through the sintered metallic pads pretty quickly. This was a combination of high bike weight, steep roads and high speeds on the tarmac.
In South America on some monstrous descents, which were all on gravel roads and not as steep and therefore not as fast the sintered metallic lasted over 6 weeks and about 1500 pretty rough miles.
Seems ceramic is your best bet, will fit your requirements of no doubt having to cope with stopping at ultra high speed
, and the price isn't really a massive issue.