I've had nothing but good experiences with DX. I've probably placed close to 30 separate orders with them over the last 2 years. About 18 months ago I needed some LED drivers they stocked for a project with a firm deadline. I ordered them just as they went out of stock, potentially wreaking havoc on the project deadline. I probably had a 4-5 email exchanges with them about estimated time of restocking and expedited shipping. In each case, I had a reply within 24 hours. As recently as 3 months ago I had a correspondance with them regarding a batch of reflectors, some of which weren't to spec. Again, a useful response came within 24 hours.

Maybe I've just been lucky?