I don't order much online but I really like Nordic Needle
in Fargo ND. They are an actual store that has been around for at least 20 years as well as having a pretty extensive website and catalog. They send out regular newsletters and product announcements on subjects you select. One of the owners designs Hardanger patterns.. which does seem to be their main focus but they are very knowledgeable on all things stitchy. The items I have ordered, I've received quickly, and they've thrown in extras depending on my spending level.
And Yarn Tree
from Des Moines IA (I think). They are a wholesale needlework supplier but also sell to regular stitchers (Although they do try and direct you to buy from your local needlework store if you have one). They are not good for buying floss or fabric from.. large quantities only.. but good for everything else.. printed charts, finishing supplies, tools, etc. And their website has the fabric calculator
I find most helpful.
With both companies, I may order things just once or twice a year. I have 2 stitchy stores near me and prefer to shop there when I need things. I order more often from Nordic Needle than Yarn Tree. I live about 4 hours from either place so I receive my packages within a day or two of ordering. But I've never had problems purchasing, returning or shipping with either one.