Main pick

Binance
Best default for most BNB buyers
Start here if you want the shortest route to BNB. For most people this is the default answer, and dragging the choice out only adds friction.
BNB
Most BNB buyers do not need a giant comparison tree. They usually need the obvious default first, then one or two backup routes if they still do not want to use it.
Coin snapshot
Start here
Pick one default and one backup instead of reopening the full exchange search.
Main pick

Best default for most BNB buyers
Start here if you want the shortest route to BNB. For most people this is the default answer, and dragging the choice out only adds friction.
Backup

Best major backup if you do not want the default
Use OKX when you still want a large exchange route for BNB but do not want to stop at the most obvious answer.
Need one more route?
For most people, Binance is the clean default. If you still want a large-platform backup, compare it against OKX.
Most beginners should start with the shortest route instead of overthinking it. If your main goal is simply buying BNB, the clean default usually wins.
Only if you already know why you dislike the default route. Otherwise, you are usually better off choosing one clear route and moving.