What in particular did they not like about the current design?

I like the "outside" design the least. I noticed that the drop shadow is curved at the bottom edges, but the box it's a shadow of isn't. A small thing, but irritating, for me at least!!

I'm undecided on the individual product images. I don't know if people coming to your site will know exactly what they're after. If they are then it might be easier to tell from an image rather than a product name. Difficult without knowing about your customers etc.

Could you maybe use smaller images on your design or have some flash scrolling section? Or have a look at MSN here where they have the "Discover more on MSN section, perhaps you could have the product images in something like that?

I also hate their Products Page, particularly the Conventional Products section. If I go to a company's website it's to find out information, not to be told for more information contact EMP. That just smells to me of we can't be bothered to do pages about these. Your product pages are streets ahead of the "outside" lot. Even on the old site.

I would maybe try a drop shadow round your new design as it tends to lift the content out of the page.

Just a small point but you missed the n out of testimonials on your link.

I agree with J on the menus. They're a little slow, but if you're losing those on the new design then I guess it doesn't matter.

It's a bit tricky if you don't know what they didn't like about the old design you did. Looks fine to me. Maybe it's that it didn't have any yellow in it...

All in all, if I was them, I'd be more than happy with the design they've got. Why they'd want to change it is beyond me...