Pretty happy with this product after my first 2 runs in it, only 2 real gripes - firstly, for the galaxy s2, its an extremely tight fit, which is ok I suppose, but I just hope it loosens off a bit so its not such an effort to use!
I agree with others comments about the size of the band too, I'm not a body builder, but my arms are a decent size and the strap could do with being a bit bigger to make it properly comfy.
Good points are quality of the materials used and the overall quality durable feel, much better than a cheaper one I've recently had to throw away due to it falling apart! Can't go wrong for £8 :)
UPDATE: Having used this for a few months, this product is actually brilliant, no signs of wear and tear, and the phone slides in and out easier now. Couldn't hope for more from an arm band - it even survived being washed with no problems!