That was a scratch your own itch project; just so you understand we (folks behind stockrow) are hobby investors who do not plan to pay for services like bloomberg and ycharts yet require tools and access to data in simplest possible form.

For us problem is that all screeners (and tools) that are available are either slow, dumb, lack flexibility, are really hard to use or expensive (or all of the above combined). So what we did with two friends of mine — we've created our dream product: simple and fast with all data freely available. It is still in it's infancy but we keep adding things that we need and improve it so it suits us.

Sorry to say but we do not plan custom metrics at this point as this is beyond our capabilities as investors at this points (frankly speaking we do not need them, but if voices are loud enough we might consider that options) but we do plan to introduce backtesting at some point.

I know about StockRover but for me UI is really complex; I need a screener where I can get results almost instantly without much thinking or clicking around.