Another point is the way the menus display and the speed in which they drop down. Along with the colours of the text which can also be a very important factor in click through ratios.

I would say you will not have any problems from an SEO point of view but from my experience showing new clients and people new to sites with the drop down menus they can be misleading.

The drop down reveals the pages but the main page that is acting as the parent of the other pages is sometimes overlooked as people don't realise they can still click on that.

I speak to people on the phone - hundreds of people and show them sites and time and time again I have to remind them they can click on the main parent button .

We are considering changing this as a result.