Just as good as any other chess sim of the era
If you're ok with static 2D chess boards and an okay Ai at best, while for most of the time, a bit too anemic and not too smart, then Power Chess is an okay game. I mean, when the game is using its preprogrammed tables and moves that have already been databased, it is pretty straightforward, though not too intelligent. But when the games progress, especially during endgame stages when many pieces have been cleared, the AI is less interesting or interesting in that it might do some stupid mistake even on the highest stages of difficulty. That is so because the positional awareness of the game is not that bright, but then again, it's not like the competition was any more mature at the time. Anyway, you can choose to play the game vs a human player, case in which you'll get a better contestant, or, you could use it to further your chess skills. The game is an interesting one, as I mentioned because it manages to be quite hard to predict later on, in end game stages, though not because it is the smartest player, but because it can do stupid mistakes. Well, as long as you're not some grandmaster, you'll be okay!