About Corian
I used to be co-owner of a countertop shop. We did everything - Formica, butcher block, DuPont Corian, granite, and quartz. I can't help you with granite transformations - I haven't had much experience with them. I will say though (after looking at your link) it looks like they are using a veneer. Granite and quartz are by nature fairly brittle materials. The impact resistance of them is directly related to their thickness. When you have something thin and brittle, you will need to be careful about dropping things on the countertop, or hitting the corners. If you are relatively easy on your kitchen, it shouldn't be a problem. If you really live in there, you may want to consider something solid.
The other thing I have to ask about though, is your experience with Corian. Is it really DuPont Corian, or is it another brand of solid surface? We took everything out of showroom except DuPont Corian because of cracking, staining, and warranty service issues. If your countertop is DuPont Corian (you can tell by looking underneath it - DuPont stamps all Corian slabs about every 3-4 feet), you should call DuPont. Staining is specifically covered by your warranty, and it should not happen. I have had Corian in both of my houses and love it (but, I also understand that countertop preferences are particular to the user). Never any staining problems - the sinks come clean without a hitch. My sister, however has Surrell (the Formica brand of solid surface). Her sink looks like the floor of a rest-stop toilet cubicle. It will never come clean!
Sorry - just had to ask about your experience. After all these years, I am still rather passionate about countertops.
Hope your kitchen renovation goes well!