HFT is not bad. Technology is democratized now. The best trading tech is available to consumers. The professional edge lies in their unlimited, low-cost leverage not in their technology. As a consumer, HFT is not my competition it is my order facilitator. A huge share of equity trades get their price IMPROVED by the market makers in order to capture the trade flow.

I love Michael Lewis. The Big Short was a very enjoyable read. I've read all of his stuff. I've run into the guy at the grocery store. But Flash Boys was just silly. Even if you believe it, the guy getting "disrupted" was not a retail trader but a broker crying that HFT was making it hard for him to dump orders on the market in 10,000 share lots.

Edit: I won't respond to every critic, I respect your views but I've given it thought and have reached a different conclusion. You can quantify that orders are filled today more quickly, at better prices, with far lower commissions, and we have tighter bid-ask spreads, more penny-wide markets than ever before, and an explosion of ETFs that give retail traders access to something that they otherwise would need a futures contract ($100k in notional value) to trade. And of course in the world of algorithmic trading, there is technology not available to consumers. But a consumer today can have a setup at home that is as sophisticated as a professional trader's setup. That never used to be the case. But the software is commoditized now. The trading platforms available to consumers, like Thinkorswim and Interactive Brokers, are top-shelf.