It's not about the price - £1 off is insignificant - what matters is who has the better content. Amazon / LoveFILM does have the advantage that for £4 more than Netflix you can get unlimited DVDs and Blu-Rays delivered to you (with newer content).
If the streaming content was similar would much rather pay £4 extra and get DVDs and Blu-Rays delivered - even if it is a bit old-school.
What would be interesting would be if Apple were to do the same!