The popularity of BR is undeniable in this thread and similar others and best wishes to all, but I want to add another shout-out for the less common Op/Tech. They work well for my needs (serious amateur, not pro), are very flexible (reconfigurable/modular), and have proven to be secure in my experience (2yrs owning).
I see some people worry about plastic clips, but I think I see similar clips are also used on the modular BR RS-7 -- and on military equipment such as helmets. I have also dealt with a fair amount of metal fatigue in my time, so metal clips can fail too.
The main thing that drew me to Op/Tech was the flexibility for rapid use on a tripod -- I want to minimize any excuses I might have to use a tripod as often as posisble (I'm mostly landscape/nature), and I couldn't find any good quick solutions for BR or others with Arca plates.
Op/Tech allows me to have a permanent L-plate, handstrap (3rd party), and completely configurable sling and neck strap -- and it's low cost too (though this was not the main driver, personally).
I have no affiliation with Op/Tech -- just a happy customer!