I think it helps a prospective buyer to compare to other products someone might be looking at:
The DGT Centaur is cheaper, has a built in battery. It has less options for setting difficulty though. And is all plastic. Personally, I didn't care for it's looks, and wondered if the options were too limited for my tastes, in terms of difficulty levels.
There's a number of electronic chess boards out there. Chessnut Air. Various DGT models. Millenium e-one. These are not standalone chess computers. You have to use them with an external device like a smart phone. Which may mean 10 to 20 years from now you might have trouble if technology changes or support drops. Personally, I didn't want to deal with externally computed devices tied to current tech.
There's a few options in which you buy a computer and hook it to a board. To me, that's better than relying on a smart phone. This would be like the DGT PI chess computer, and some of the Millenium boards. I was especially pleased with the Millenium options, such as the Chess Classics Exclusive. Which has a sensor board, and a separate dual engine computer you plug into the board. Nothing wrong with this other than price, and the need for yet another separate piece to deal with.
I chose the King Performance for these reasons:
* Almost 100% standalone, except for battery pack ( Volt)
* I wasn't that excited by using this to play online with others, so the need to buy the expensive and annoying Chess Link wasn't a deal killer for me, as I may decide never to buy it
* I wanted a wood look
* I wanted the King program, for it's flexible options
* Having to push down on squares wasn't a deal killer for me; there's even an advantage, in that you can use any pieces you want, as the pieces contain no special gizmos to work with board sensors
I find the menu easy to use. Especially the Comfort menu which is probably sufficient for a lot of players. The manual seems clear. Simply plug it in ( or plug in the Volt which I suggest buying if you want to be able to play anywhere.) Select your level, such as a Comfort adaptive level. Setup the pieces, then press the New game button. Then just press the starting square and ending square of your piece. The King Performance will then light up the squares the opponent's piece is moving from/to.
You will want to review the manual, for understanding castling, pawn promotion, and any other special moves. Also, you will probably want to know how to take back moves.
Sometimes I get confused as to why I get some error. One cause of error, is where the board thinks you pressed the square twice. After some practice, you will figure out how to cope with this. One common scenario is that it thinks you pressed source square twice. Just push it one more time, then press destination.
When in doubt, use the somewhat akward feature in the menu to confirm board state.
It's mostly easy to use. I do suggest reading the manual carefully. The Comfort manual came with the board. You can download and print out expert manual.
Some general comments on things that are perhaps not ideal:
* It would be lovely to have the ability to play the comfort levels in expert mode, because the expert mode display is more helpful, showing the current book opening ECO codes, and more information on the current eval. I can kind of understand why they separated this. You can simply play the fun levels in expert mode, but I don't think they are adaptive. But you can probably find some level that works for your ability of play in expert move as there's a lot of options
* Sometimes I get confused as to the state of the game. Especially if I am trying to take back moves. I think with experience using it, I will find it more easy
* Due to the small display, the menu option to check where pieces are on the board isn't very nice to use, just realize you will have to use up/down arrows, as you can only view top or bottom half of board
* Personally, a hint button would be really nice, along with a check board state button. But the menu is mostly easy to use. Learn what's in the menu
There's a lot I have not tried to use, like setting up a position, or getting the computer to play a specific opening via forcing moves. I apologize for the incomplete review, but I don't expect to exercise all of it's features, and thought I should write a review from a new user perspective.
Overall, it seems to be a good product, which pretty good software running inside it. Durability is something I will have to see, when I have owned it for some years.