What is a good price for windows and doors?

I am wanting to get my windows and doors replaced and have had a survey (well 2 in two days) done by Safestyle UK. Now I am aware of some people's opinions on this company, but they have also got some good reviews. Their latest quote is 6500 for 9 windows and 2 doors. I've got a semi-detached home.

My questions:

Is this a reasonable/good quote?
Are Safestyle really that bad? Has anyone got anything positive to say about them?

Thank you in advance for anyone who gives me any help