Equally. All modern engines play at so high a level that distinguishing between them is really only relevant if you're playing engine-assisted matches.
Some GM's will swear Hiarcs, because it seems to make better use of positional principles than some other engines, is more useful as a study aid for OTB play, since the lines will end up being more intuitive for you to play and understand in your own games.
How good is Hiarcs compared to Houdini Aquariam or Rybka 4 in chess analysis of one own games and the other functions in general.Im about to buy one and i want some help my from chess members on choosing the best.