I'm debating repurchasing Fritz again (bought it last February, then had no time to play so it ended up being sold for a $30 loss...).  After I bought it last year though, I realized just how much more software there was, so now I am at a loss for what I ought to buy.  I by no means need the strongest engine to give me a good game, but I would like it to have as much instructional material included as possible.

Some of the software I would like to know the differences between is Rybka, Fritz, Shredder,Hiarcs, etc.  Are they just the different names of engines?  Is it primarily an interface/cosmetic difference?

This topic has been discussed at lenght on several posts here at chess.com.

If you do not get any answer:

I. Here is a link to forums on this topic:

http://www.chess.com/search.html?q=chess%20engines

and another one:

http://www.chess.com/forum/view/general/chess-engines2?lc=1

2. You can alternatively type a search string in the search box at the right hand top corner of any page, where it says: search the forum and you will get plenty of forums on the topic.

Good luck!

All those engines come with the same interface, and mostly the same features, including instructional materials. In times past, Fritz had one or two features absent in the others. I'm not certain whether this difference remains.

Rybka is bar far the strongest.

Hiarcs has a more human style, and is usually a little stronger than Fritz.

Many engine devotees claim that Shredder understands sacrifices better.

Save your money download for Free Arena 2 the 18 mb exe.file which comes preloaded with several strong chess engines including rybka 2.2n2p32bit Free 2988 at 5min blitz an 2978 at 40 in to hours on a multiple cpu computer its a bit over 3000 a stronger chess engine than fritz 11 at 2968 at 5 min blitz.Also you will find here at the free chess download section portable winboard x pre loaded with rybka 2.2 an the rybka performance bin opening book along with a small naminov endgame table base also check out scid great free database an chess assistant 7 light database  which also loads uci engines such as rybka or toga2  2922 blitz rated or the mayura chessboard which loads uci engines all this an more are FREE FREE here at chess.com free downlods or check out zarkon fischer.com for more great free downloads.Save your hard earned money as there s tough times a comin.