Just completed W4, R2 and had to write how fantastic I feel. I really did not want to go as the weather sounded awful, pelting down on my kitchen window. Once I got out there, it felt surprisingly pleasant to run in the elements.
On a more general note I've lost half a stone since starting the programme, my energy levels have improved and I'd even say that I feel brighter, more alert and more positive about life.
And all you have to do is get those trainers on and get out there! Probably too soon to say it's been life changing but I certainly think my eyes have opened to the possibilities ahead.