Overclockers used to be down right awful for customer support in my opinion if i'm honest, they were fine until something went wrong then good luck getting a peep out of them.
Over the past year however there has been a noticeable improvement in that department, I've also noted a few mentions on the forum of customer services being their 'current focus'. IMO this has paid off and i'm now more than comfortable to buy products from here. I've had one experience with their 'new' customer services involving a faulty hard drive caddy, i got replies to my emails within an hour, a replacement was sent to me within a week and the postage costs at my end were refunded promptly. Many would argue that 'that's to be expected of a company', they're right, it should be, but i'm merely trying to point out that overclockers is no longer deserving of the questionable reputation many used to hold against it.
In short, they're a good retailer and i wouldn't be worried purchasing from them.
Oh and, the customer services forum is great.