I'll go out on a limb here and state my own personal conviction
If one wants to invest in securities, and has an aptitude for coding,
then algorithmic trading is the only sensible approach. Period.
Who want's to invest in securities? I'd speculate virtually everyone who is saving for retirement as a starter. Who has an aptitude for coding? I'd speculate not many. Judging from my personal experience, as well as a lot of the posts here in the Q forums, developing a logical robust trading process within the framework of python code is beyond the ability of most people.
Why do I say it's the only sensible approach?
First, it saves time and isn't prone to errors. If the ONLY thing an algorithm did was to automatically execute trades which would otherwise be entered manually, then that seems reason enough to move to algorithmic trading. I have spent many hours manually calculating number of shares and entering trades into the E-trade portal. Not a good use of time.
Second, it allows for backtesting and some rational basis for choosing an investment/trading strategy. The ability to simulate how investment decisions would have played out places algorithmic trading on a whole different level from other approaches. How else would an individual decide on an investment 'approach'? I'd say the most common is to invest in 2 or 3 mutual funds. Rotate every once in while (when one thinks of it) and choose one that did great last year (hey this energy sector fund went up 34% last year - I'll buy that one). There are of course other approaches but they generally require putting faith in some 'expert' or 'system'. Algorithmic trading at least allows for the ability to do credible comparisons between well articulated strategies.
Third, it provides very important numbers beyond simple returns. I feel that volatility, drawdown, and beta are more important than raw returns. These numbers can be estimated with backtesting an algorithm, but are VERY hard to deduce from any other kind of investment approach.
Now, I sense the theme in this post was if anyone had any 'big wins' or even 'consistent wins'. Unless there is big money why should I bother? That seems quite shallow. That seems quite like asking 'why should I bother exercising if I'm not going to make it to the olympics?". Even a little exercise would benefit most people. And who knows, maybe one can make it to the olympics? But you'll never know if you don't even make that first effort.
I have had a live trading algorithm on Robinhood for awhile and it's pretty much matched the backtest results. So far I don't see any reason to believe it won't continue to do so. The annualized return 2011-2016 is 21%. Volatilty 12%. Max Drawdown -11%. Beta .11. Leverage 1. Some of the past 5 years have a backtest showing annual returns only in the 8-10% range but they are offset by some much better years.
A couple of caveats... This trades in leveraged ETFs even though the leverage is technically 1. The ETFs started in 2011 so that's the earliest backtest date. Not a lot of history but something. The last few years have been good for both bonds and stocks so that may account for much of the gain.
Now, I'm not saying that this is by any means a great algo. It's not Q material because of the leveraged ETFs (and other reasons). However, it shows that with a relatively simple algorithm one can 1) automate trades 2) have a degree of confidence that the strategy is sound 3) have numbers that can be monitored (ie beta and volatility) to see if things get too out of line from expectations (maybe stop the algo?) and 4) has better returns than the mutual funds in my 401K.
A good place to begin a personal success story is with a simple ETF strategy. ETF strategies such as this are far more than simple beginner investor escapades. These simple ETF strategies can be used as 'top down' high level frameworks to create better performing, scalable stock strategies. Beginning with an ETF strategy such as this (ie 45% 3x leveraged SP500), create a stock buying strategy which duplicates only the SP500 portion. Keep the other 3 ETFs in place but trade a basket of stocks which mimic (or ideally outperform in volatility, beta, and/or return) the SPXL ETF. Having the baseline of the leveraged ETFs, one can then replace them with stocks and un-leveraged ETFs and then add your own leverage to potentially outperform the ETF version.
Very few can probably put together the ideas and code to create a Q, hedge fund potential, strategy. Much like very few can put together the ideas and effort to create a multi-million dollar company. However, there are not only the Bill Gates and the Steven Jobs who have succeeded but many many others who did make the effort and did succeed because they took the initiative, availed themselves of technology, and collaborated with other like minded individuals.
The Quantopian platform is much like a virtual silicon valley for quant entrepreneurs. Not everyone packed their bags and moved to San Jose and not everyone who did struck it rich. However, I'd say most who did try have been better off than not.
Anyway, just my opinion(s) for what it's worth.