I have just done a lot of research into solid worktops so corian/quartz plus the cheaper option of a "surfaced" worktop ie Bushboard where they have a thin layer of either quartz or man made resin/polymer tops also Hi Macs, Maia, earthstone, silestone, wilson Art (when I say I do research, I really do a hell of a lot) 
The best thing I found for advice was this from an independent kitchen designer and all the comments below from people who have had it fitted and then had major cracks. 
Plus I also got info from forums from actual kitchen fitters etc
The basic thing seems to be that firstly, the units underneath have to be completely plumb and square.
Having seen an American company who fit granite worktops install a kitchen, and the attention to detail of using a laser level to get the cabinet completely level, it would seem imperative to get this part right.
Secondly you are meant to get a trained fitter and one recommended by the company whose product you are buying to fit the worktop, because they are meant to have been on a training course.
What I will also say is that if you have a look at samples of these products they appear scratched, the argument being that the samples are capable of scratching each other however the product should be hardwearing. But if you go somewhere like B&Q where they are on a stand or a pull out drawer then the samples aren't touching each other. So theoretically they shouldn't be scratched and yet they are.
Good luck! Me? I'm having laminate worktops because the thought of spending £2k plus on worktops and then it cracking would send me over the edge