I haven't had any problems with mine. They are a very light cream color too. My kids have colored on them with markers and pens and spilled all sorts of stuff. I make sure to wipe up acidic spills quickly (vinegar, OJ, etc...). Everything has come out with a swipe of a soapy dish rag.

The only problem stain I've had to deal with in the last 2 years actually came from a Christmas present. It was wrapped in some shiny wrapping paper and it sat on my counter for a day. When I went to move it there was a bright red stain from the red in the paper. The dye must have soaked into the poly/resin layer of the counter. I started with soap and water which faded the stain but did not completely remove it. Then I sprayed it with stone cleaner and that faded it more but I could still see it slightly. The next day though the stain just seemed to have disappeared.

Honestly Quartzite is an amazing project but it is normally more porous then granite and thus you will want to clean spills quickly. Since countertops are a big investment I would recomend going with a Granite or something like a Caesarstone.
Here are a few videos that might help you decide.
All about Quartzite

Lisa talks about materials in this interview.

Sorry - just realized you said Quartzite. I have quartz which is a different product and is not porous.

Have you thought about recycled glass? its green and very durable. We're going to remodel and I'm pretty sure that's what we're going with. Check out vetrazzo.com.