The XTOL datasheets seem to be more thorough than any others, and the times seem to be very good for all the combinations I have tested. I don't usually find I need to vary much from the published times. And I love that they give times for multiple temperatures in many combinations. The fact that I can look up a good starting point for most films in replenished developer using rotary tubes and sheet film at 75F is great. Besides the great results this sort of trustworthy documentation is invaluable. Like the idea of the massive development chart, but with times that actaully work (yes, I've had mixed results with the massive development chart).