Whether or not they're drastically modifying the value of the market is really hard to say, I don't think we know that fully. Honestly, I don't think we understand it that well yet. You can make some fairly reasonable assumptions that it doesn't cost the typical investor that much over his investing life though. I think part of those assumptions are that the high speed traders are simply trying to move faster when they acquire knowledge though, to me, that seems kind of elementary for the guys that invented all these exotic synthetic derivatives and ways to mask risk and shift it around... You couldn't tell me that they aren't trying to think up other uses for those technologies if they exist; like maybe you can measure what counter parties are doing with high performance timing and get some insight.
Fundamentally, are they leaving that few dollars on the table or are they picking them up? It may only be a few dollars but it's a big difference between paying it and taking it.