Martyn – thanks for reminding me about Kayak, I know you have mentioned it before here and I now I no longer have a secretary to do my bookings I am taking more time on the research.
It is noticeable to me the varying performance, stability and ease of use between different websites. For example when I recently booked a flight for my daughter with easyjet I was amazed at the amount of ‘just one more thing’ advertising I had to plough through before I could make the booking. Lufthansa, fast and simple as might be expected but they really do like you to ‘log in’ and the system gets a bit grumpy if you continue without doing that. British Airways is my favourite, fast, well laid out and efficient. A good example of a customer focused design.