Can vouch for scan being honest and reliable as well as reasonably well priced. Had some stuff tehy sent me break recently and they sorted it very quickly, was slightly disconcerting to have my emails answered within a couple of hours, i'm more used to waiting a week or so and then having to spend half an hour waiting in a phone queue..
Not had problems with ebuyer, but have had problems with citylink who they use to deliver.
lowestontheweb were quick + painless but not had to test out their returns procedure.