I got really surprised when I read some of the negative comments.
My experience with All4Running was extremely satifying.
I bought 2 pair of shoes early February. They shipped them the day I ordered them (or the day after) and I received them within 2 working days... so they were very reactive.
Unfortunately, after only 30km one of them "broke"(the shoe was with a carbon plate and the carbon plate broke). The shoe was obviously defectuous.
I first called All4Running. The person I had on the phone was extremely kind and he advised me to send an E-mail explaining the issue, which I did. They reacted very fast to the e-mail and asked me to send the shoe back, which I also did.
It took a bit of time between the time I sent back the shoe (23 of feb) and when I received the new pair (07 of march) but this was not because of All4Running but rather bpost/DHL (transporter) as they received the package only on the 28th of feb. I believe I called them on the 3rd of march, saying I didn't receive any news (at that time, I didn't know they received the package only on the 28th of feb and, again, the person I had on the phone that day was very kind and reactive), the day after, they shipped the new pair, which I received today, the 7th of march.
So, overall, extremely satisfied of All4Running service and would recommend to anyone.