Great for trainers - good value, free socks and quick delivery (I recommended the express delivery for a fiver - you get an email from the courier which allows you to change delivery day if required, then on the day you get an sms telling you the hour window of the delivery!).
However for other kit I have had a pretty bad experience (brand sizing charts were not accurate and the returns / exchange process is not good at all - email replies were very slow and it took 3 weeks for them to process the return only for the different size kit to go out of stock despite the website still allowing orders in that size!).
So a mixed experience for me.