CRC have always been good for me. Once I was sent a chain with the joining pin snapped, I called (still NI at that time) them and was given a £15 voucher and told to send the chain back. When I told them I had managed to fit the chain they let me keep the vouccher for my troubles.
Treds have also been good, only once has an order taken longer than the stated time on the item page. On that occasion I was emailed by a human who offerd a refund if the new time frame was too long.
One item ordered from Evans, last week arrived in 2 days. I have ordered my first from Bike dicount.de this week, so hopefully they will be as good.
Swinnerton Cycles have also been good.