Silestone is 90+% quartz, it's not plastic. It's also almost
indestructible. Before I bought it I got a sample piece and tried to
burn it using matches and a lighter. They left a dark spot but it
rubbed right off with my finger, didn't even need water.

I also hit the sample really hard with a hammer. No damage. Knives
won't cut through it, and though I occasionally cut on it I usually
use a cutting board because I figure it's so hard it'd dull my knives
(quartz is something like the third hardest substance).

I bought my Silestone at HD a few years ago-- the installers were the
local Silestone franchise, not from HD. They measured and three guys
came back a couple of weeks later to install it (with an undermount
sink, which I highly recommend). No problems at all in the 6+ years
I've had it.

It looks brand-new, it cleans with a wet paper towel, it won't burn...
I see no disadvantages with the possible exception that if you have a
really, really long run of it I think the pattern eventually repeats
(although they may have changed that in the past six years).

I'd probably be happy with any sort of plastic countertop in a
bathroom but for a kitchen I highly recommend Silestone (or one of the
equivalent other brands).

Shaun Eli
www.BrainChampagne.com