Well, this is subjective and will depend on the opinion of everyone so the majority will say what's the best for them.
Have you tried playing in on bk8? If you haven't, you can take time and play with them to check it out. The two bookies that you've mentioned are also known.
But if there's someone who wants to check the other bookies, this is what's good in this community. There's a lot of choice that you can spend your time with to test almost all of them if you want to.
You should not only rely based on the ideas of other members, as simply they have their all time favorite that makes them work for them. But there are a lot of best online sportsbooks that you have to choose, and you can only tell which one will fit for you if you start exploring and making experience with them. Each sportsbook has its own great offers and bonuses, so try it with yourself and only by then, you will have an idea which works best for you.