They are in partners with the local LGS's, and you still end up paying local sales tax, up to 8.5% depending on where you have it shipped to. Plus, their prices are a little higher than others.
The other mentioned online dealers you pay there, sometimes pay shipping and insurance ( cheap) then only pay FFL fee when it gets to your LGS.
Kentucky Guns seems to have good prices too.
With all the online dealers, make sure that the listed manufacturer model number matches what you are wanting. Sometimes the pictured item doesn't match the model number, and you could end up with the wrong firearm.