a) What would be better, the latest edition of Deep Fritz or the latest edition of Deep Rybka?
b) Is Deep Blue stronger than Fritz and Rybka and Houdini engines, or is it weaker?
b) Deep Blue was dismantled, and was different in that it was specialty hardware not software as engines like Houdini and Rybka are.
That said Fritz and Rybka are certainly much stronger than Deep Blue was. Deep Blue looked at more positions, but its evaluation and I would guess pruning were weaker (i.e. looks at more useless moves than present day software).
Or the most obvious reason, that it barely beat Kasparov in the 2nd match (lost the first) while today's top software would be favored in a match while running on a laptop
Lets say I wanted a good analysis engine with a large database... Deep Shredder 12, Deep Rybka 4, or Deep Fritz... 13? I dont know the latest version of Fritz.
The free version of Houdini, 1.5a, is just as strong, if not stronger, than Deep Rybka. And this free version of Houdini is without question stronger than any version of Fritz.
Also, the latest versions of Stockfish, Critter, and even Komodo, again, all free, are all stronger than Deep Shredder 12, or any version of Fritz. A Google search will give you the download links. Together, these four free engines are all you need. There is no reason to purchase Shredder or Fritz or Rybka, unless you want to.As far as large databases, these are also several databases available to download online. You can also create your own, via The Week In Chess's archive section, of their pgn files.And finally, waffle is correct. All of today's top chess engines are all noticeably stronger than "Deep Blue."
I bought Deep Fritz 12, but I don't even use it. I'm running Houdini though the chess program that came with Deep Fritz 12 (which is great). In engine matches I set up, Houdini won against the engines that came with the software (Crafty 23.01 and Deep Fritz 12). You can download Houdini for free here.
I like Critter's playing style. It's probably a tad weaker overall than Houdini 1.5 (very small differences), but his moves have certainly more "human logic". Oh, and Critter, according to his author, will always be free of charge, while Houdini went commercial.
On old hardware, you'd rather forget the strongest engines (they stress the CPU to its limits) and use Stockfish, which is a bit weaker (still much superior to Fritz/Shredder and such) but leaves considerable breathing space to the hardware.
What about free GUI's?