Unfortunately I was getting compartment syndrome when taking it - generally hitting me after a days rest. The scientific evedince of gains from creatine for long distance runners is scant anyway.
I appear to be getting faster by losing weight. I've lost half a stone since Xmas and whereas I found 7 minute miles over, say 8 miles, hard work before Xmas, now it feels easy. I am aiming to lose another two or three pounds to get my BMI closer to 21 (in line with the guys I train with at work) and then a 2.50 marathon is on.