My favourite is Vichy Dermablend. I don't find any of MAC's have good enough staying power. Dermablend is awesome because it really, really stays(very sweatproof, important in summer heat!), you can really build coverage(it looks full coverage without feeling heavy), and the coverage is so good 95% of the time you don't even need concealer, just be a bit more generous with the product under the eyes and over blemishes. I was an immediate convert to it when i was doing a huge wedding with another MA and she was using it and suggested i try it. i used it on a few of the maids and my god, it was fantastic, i went out the next week and dropped $150 on all the shades, that's how much i loved it. and that was after investing in a whole bunch of foundations right before(cinema secrets palettes).
they do only have 5 shades, which isn't *quite*enough(though those shades are really well selected and do cover an IMMENSE # of tones), however, when i have a problem with matching, mixing it with MUFEs corrective concealers(in the big, flattened tubes), like the yellow, reddish, and greenish ones, always works perfectly and doesn't compromise the finish/coverage. the finish is flawless, too.
I have several of the cinema secrets palettes,and I love them - you will never, ever have a problem with matching skin with these - it makes foundation matching simply brainless. however, i only use them on photoshoots when i have access to the model for touch ups. they don't set that well on oily people(like dark skinned women who have naturally oily skin) and will migrate, even with a primer and setting powder, so because of that, i won't use them for weddings unless i absolutely have to and the bride has rather dry skin. + you need to use a seperate concealer anyway, their coverage isn't satisfactory for concealing IMO.
I do agree with Kiseki's comment: "I would go for Make Up For Ever's Face & Body or Face Atelier. Both don't have any SPF and look gorgeous on skin with a very good color selection." MUFEs face and body is pretty darned good, and the buzz about face atelier is amazing.
about the colorscience... what product is it that you like? i haven't found any powder foundations that have good enough coverage for weddings, and i was looking at the colorscience website and the only powder foundations i saw were mineral foundations... I adore mineral foundation, but only on myself for day to day, and for the rare occassion i do work for people who won't be getting their photos taken. stay away from mineral makeup for weddings because most of them contain "natural SPF" in the form of titanium dioxide and zinc oxide, which reflect light, make people super pale/ashy in photos. this is probably the #1 don't of photographic makeup!
also, what is your concern about a powder not being hygienic? powders are poor places for bacteria to live/grow so you don't need to worry about that. if you are concerned, you can use a tissue and wipe off the top surface of the pressed powder to be extra-safe, but you really don't need to be concerned about contamination of powder products unless you wet them frequently and keep them in a warm place. hth!