I agree with your points. I think my main focus at this point is futures, particularly CME and CFE, so maybe it would be worthwhile to buy data from Nanex on only these two. I love that the nanex data gives me just a no hassle way to replay the entire book and I trust their data a lot more than data I would database myself. This is actually something I've considered in the past; especially because I believe they give a 10% discount for a year+ worth of data, so I could've save myself a year + of feed listening and potential headaches that would accompany it. My biggest concern with them though (as I've detailed to @IAS_LLC) is the 25 millisecond stamps. 25 milliseconds is low, but there could be hundreds/thousands of messages in 25 milliseconds, so I just wonder how much closer that gets me to a realistic Backtest than trade only millisecond data from iqFeed. I don't even really know what a realistic 'delta' is for the time it takes me to place a trade. Any feedback from you folks about which would be better? Maybe I could combine the two datasets somehow? Also, I'm sorry, but I can't really tell you what my strategies require, I may be putting the horse before the carriage in that sense. I'm admittedly guilty of just obsessing over data quality and have neglected to really move past it, but I also feel like there are probably worse things to obsess over.