P123 has the following features which I find valuable.

1. The backtester is intuitive to use. You can construct and backtest your own screens with super easy to understand rules and factors (unlike the cryptic symbols you need to learn in gtr1). Yes, the backtest period only goes back to 1999. But that's fine with me. The past 24 years has 4 bear markets within decades-long bull markets, so there were a variety of market conditions to test robustness and drawdowns.

2. You can run a simulation of your screen in real time. Just put in the starting amount and hit Run. You get alerts whenever you need to rebalance, and it tells you which stock to sell and exactly how many shares of the new stocks to buy. You can even send the buy orders to your broker with 1 click. You can log in to see your account value any time, and view the performance against the market.

3. They have a number of "model screens" which they have been tracking over the years. 7 of these have beaten the market over the past 10 years. One of these has tripled the market's 12% CAGR during this period, and a few of them have delivered over 20% CAGR.

4. They have a number of "community" screens that have been built by P123 subscribers. Some of these require an extra payment to subscribe, others are free.

If you just need to see current screen picks, and are OK with a 5-year backtest, the Premium plan is $29.95/mo. If you want a 20-year backtest plus more advanced features like rolling multi-year returns, get the Pro plan for $49.95/mo.

Well worth it for me. I need a backtester and screener that I can depend on.