I have Mavic ceramic rims on 3 of the 4 bikes in my fleet.
First installation was my Spectrum touring bike in 1996. Nobody seemed to make a ceramic-specific brake pad at the time --at least nothing that fit my Campy Record dual pivot brakes. Went through those pads in about 3 months. Replacement set has been on ever since --thousands of miles.
OTOH, my Serotta has had ceramic rims for 6 years with Kool Stop green pads. No problems, no issues.
In general ceramic rims are like the first time you drove a car with power brakes: a bit touchy, but you get used to it. Performance is outstanding in the wet. I've gone over Alpine passes in pouring rain and had a relatively normal descent --something you can't say about conventional rims. Whether you really, really need the green ceramic-specific pads is debatable. Your brakes will be a bit grabby with conventional pads, but that may vary depending on the particular pad compound. If you choose this route, get a second set, as you'll need them at some point. Otherwise, order a set of the green pads when you do the wheel build.