I had this comment and question posted to one of my previous blog posts:
Your estimated ratings look a bit strange but it seems that Stockfish is much stronger that the other engines.
I took the list of ratings from the wikipedia article on chess engines. Note that the ratings in the article and also the other ratings you will find about the internet (e.g. this one here: http://www.computerchess.org.uk/ccrl/4040/ ) assume certain playing conditions for the chess engine, as well as certain hardware. Remember that back in the 1970s and 1980s all of the good chess engines ran on dedicated hardware, even mainframe computers, that was well beyond the capacity of us mere mortals to pay for.
Yes, stockfish is the strongest of the freely available chess engines. The current version of stockfish is rated 3253 on the CCRL list with a 64 bit CPU (that is what I have) although the CCRL list doesn't completely identify the full system specifications. Doubling the CPU and memory of a computer used for running a chess engine is estimated to add about 50 points to the ELO rating of the chess engine, and so saying that "stockfish is rated 3253" depends a lot on what you run it on. It may not be as powerful on the little netbook computer I take on holidays with me as it is on the big network server I have at work.
Would you nonetheless recommend an other engine? And which one in your list?
Let me start by saying that I am a much better software engineer than I am a chess player!
I am quite fond of the idea of using many different engines and switching between them depending on what I'm trying to do. Different engines have different playing styles just like different players have different playing styles, and so it is good to play them all.
For analysing games I like to use stockfish. I have played some games in the past where I thought I did reasonably well, and stockfish has pointed out some mistakes that I made and didn't spot (and that my opponent, fortunately for me) did not spot either. Well maybe I learned something through that analysis and maybe that is good for me.
For playing against an engine I prefer to use a special type of chess engine that is not on my list. It's taller and more physical than most of the engines, and walks around on two legs. Let me say why.
Firstly I will point you at a couple of articles, this one which I found quite good, by Natalia Pogonini: http://www.chess.com/article/view/chess-engines-evaluations There is another article by Roman Dzindzichashvili which I also can't find at the moment which makes some good points about playing against engines. However let me give you my take on it.
I don't always make the best move in chess. Sometimes I see quite a good move which I would like to make, but I can also see a very good defence against it. Sometimes I make that move anyway, because I am hoping that my opponent won't see that defence, and I can also see that if I make that move and my opponent does not see that defence, then I will have a winning position (or even checkmate). So I take a bit of a gamble and hope my opponent makes a mistake. Well how often I do this depends on what level of player I am playing against, but I think you get the idea. I use a bit of intuition -- if I think my opponent wants to attack down the queens side and I have a strong king side attack set up that I think he or she will not see then I will go for it, as an example.
A chess engine won't do that. A chess engine will make the best move it thinks it can make. It won't use intuition or guesswork, it is just a computer program.
Some chess engines are of course programmed to make mistakes but of course that's not the idea of the engines on this list. I have an android phone and there is a free chess playing program on it that I can always beat at any level up to level 5 because it always makes the same mistake in the open Morphy variation of the Ruy Lopez. Well that's a bit boring, but none of the engines will make that mistake.
So maybe playing against a powerful engine will help you tidy up your chess and help you make fewer mistakes, but it is not the same as playing against a human.