I have ordered hundreds of thousands of dollars of stuff from McMaster, mostly in small orders. Not once have a received the wrong thing, not once have I been overcharged for shipping. Rarely when something has to be returned there is never a problem (you don't need an RMA, just ship it back). Not once have I received a "special sale offer", not once have I been charged well over manufacturer's list price (a staple of Grainger for example). Nearly always I receive the product the next day, the inventory and delivery times are always accurate.
But I will complain still: they won't tell you the brand of the merchandise.
Other than that, perhaps the best e-tailer of industrial goods on the planet. Website second to none, pricing not the cheapest, not the most expensive, just constantly reasonable, and customer service outstanding.