I'm no expert so won't hand out advice, but from personal experience I have been left with the conclusion that simple is best. On two occasions I have taken out mortgages which seemed fine at the time and a really cracking deal only to find that when personal circumstances change they suddenly are not so good anymore. In one case I was hit with interest rates going up to 15% (thanks Maggie) and with the other I was mis-sold a mortgage capital payment plan by a large and very well known financial institution.
With the high interest rates I had to just take that on the chin but it took 7 years to recover financially. The mis-selling saga ended up as a civil action that I won and at least got financial recompense for.
The length of time you will have a mortgage for almost certainly will include some form of major change to your personal circumstances such as divorce, redundancy, children, illness etc as well as the economic and financial condition of the country we live in. You never think it will happen to you...until it does. Luckily I'm out of all that now...wish I had had the benefit of hindsight at the time of making the biggest single financial decision of my life.
