I have always gone for Fixed rate mortgage as I'm someone who likes to know that my mortgage payment will not change month to month.
However, this is a personal choice as I did not benefit from the low interest rates when they dropped for several years as I was in a 5 year fixed, so be sure you can tie yourself in as rates can go up as well as down.
Halifax has always been quite good at explaining your options as far as my experience is concerned. Also, I did have a period when made redundant that I was struggling with my payments. I was very impressed with the consideration that was given and my mortgage payments were reduced to a more manageable amount for one year.
I think all mortgage lenders should offer this in my opinion, but some are better than others at truly considering your circumstances and needs.
10 out of 10 to Halifax who really helped me out at a difficult time in my life.