I hope we could both of those agree this sentence is Incorrect mainly because "great" is undoubtedly an adjective, and can't be the subject of "is". The same is true if you set "the best" in that location. It's easy to argue that "the best" may very well be proper https://jasperydvjv.mybuzzblog.com/18119379/how-much-you-need-to-expect-you-ll-pay-for-a-good-affordable-lawyer-in-dha-karachi