I had the shiny black dash on my first up which is amazing.....except the dust it shows. So when i swapped the car for a tungsten silver up, i spec'd the silver dash. It still shows dust - but not as noticeably.
Got the shiny black dash on my Move Up! Looks nice and refreshing after plain old grey in the Focus but it shows up dust and hairs (especially dog hairs!) very noticeably. I have a small car Hoover and dashboard wipes that I use every couple of days to try and keep on top of it.
If I was buying new and had a choice I may have gone for a different colour dash but whichever you choose it looks far better than plastic grey.
I have a Mayan Blue (or Cornflower Blue as it's called here in Ireland) High Up 5 door on order and I've asked for a colour dash too. Do you have and photos of your blue dash? I can't find any of the blue dash on Google.
I ordered it eight weeks ago and I still won't have it until the first week of September. I went for the leather pack and the sunroof too, the sports pack is standard here. I'm really looking forward to getting it, it'll be my little pride & joy!