I buy most of my gear from B&H, and have since the late 1980s. I confess that a big part of this is their Payboo credit system, whereby the amount of the sales tax is paid by the bank. Sales tax where I live is close to 10% so that's a significant matter. I also have found B&H simply to be a good merchant, period. When I went to Manhattan a few years ago (a long ways away from California) I was really impressed by the brick-and-mortar establishment, including the friendliness and helpfulness of the staff.
For highly in demand preorders, I have found that there is perhaps a downside to B&H's success. They get overwhelmed with preorders and so they have big waiting lists. For a couple of big ticket preorders in the last year or so I have patronized Precision Photo in Austin, Texas. They got me my Olympus 150-400mm zoom in timely fashion, asking only for a $700 deposit. I have a deposit in with them for my Z9. For my 500mm PF lens a couple of years ago I looked around and got one from B&C Camera in Las Vegas, so kudos to them, also.
I confess that when I decide I need an accessory or replacement of something I have lost (a camera eyepiece was the latest thing), I find it easiest to simply order online on the spot, rather than driving down to a camera store which may or may not stock the item.
I would like to support my local camera store here more than I do (there is only one left), but they are the ones who require full payment on preorders, so they have lost some big sales from me as a result.