When it comes to trades one trade to another looks exactly the same as flipping a coin, but it's not. The percentages won during trades, how long the trade lasted, drawdown and the duration of the drawdown all have to do with what kind of edge you're using.
My daily systems use pairs on qid and qld, and win 0% or more 88% of the time.
My intraday systems based on price physics win 95% of their trades and 95% of their days, but this is due to capital constraints. My research on this system probably would not have more than 10 losing days in any arbitrary 3 year period.
These results are as close as you can get to having a perfect system and probably is something you could call a holy grail.
Both really do well, and to put it mildly the strategy developer doesn't usually worry about implementation until he has his confirmed walk forward results, so now I'm discovering what settings to use before I put these strategies onto some co-located servers.
As far as holy grail, I'm sure you'll hear more from me throughout the years about it.