I've had some bargains from SK. You need to be careful to check the auction location as, while most of the kit is at Hillington, some can be from Inverness to Devon.
It does tend to put off casual "ebayers" as you need to lodge a deposit (which is 10% of your spend, so depositing the minimum of £100 allows you to bid £1,000), add VAT to the final price and normally pick up on a Friday morning.
That said, there can be bargains and, as SBF suggests, the unsold lots are worth a browse on a Friday just after the auctions closed.