In general, hitting a soft 17 in blackjack is not a good idea. First, the house edge on soft 17s is about 1.5%, which is much higher than the edge on any other card. Second, soft 17s are often played as “natural” cards, which means that they are automatically placed in the player’s hand without any decision by the dealer.
This increases the chances of getting caught by the dealer and losing the hand. Finally, if you hit a soft 17 and the dealer chooses to stand, you will likely lose even if you have a good hand (since the dealer will almost always hit if he has a natural).
