Coinbase has been in the crypto business since 2012 while Binance launched its platform in 2017 only. So based on that I think Coinbase has more users but we don't know the exact numbers.
Exactly Coinbase has been here for long time and also has a good record because of their best support compared to other exchange so basically its coinbase is more users than Binance
I can speculate that Binance may have around 10 million users as of this time and will continue to grow based on the strength of their BNB and the man himself, - CZ.
No wonder they are the fastest growing exchange now and has a potential of growing more over years so lets answer this question in the next 5 years for comparison because for now its not fair for Binance to Ben against coinbase