I've tried more than 15 gambling sites over the years.
I would say the top 3 best online gambling sites are:
Red Dog casino - Best overall. No fees, fast payouts, lots of games. Welcome bonus of $2200. BetUS casino - Lowest house edge, almost instant payouts, they have a sportsbook too. Welcome bonus of $3000. Betonline casino - Best for slots. They also have a sportsbook. One of the oldest and most reputable gambling sites. Welcome bonus of $2000.I've used these 3 for the past few years without issues, all of these gambling sites are licensed and regulated.