I personally feel Data Trails is not a good book. It has a very short page count, not a lot of crunch, and doesn't add anything, other than playable AI rules. Which is pretty cool if you want to play an AI. But I feel really let down by the modding rules, expanded host rules, and lack of cost for NPC things (specifically hosts and wireless negating paint) as I feel its important that the PCs and NPCs are playing by the same rules to a degree.
Chrome Flesh is pretty good though. A lot of new toys in the -ware space and some interesting advance medical rules. I also enjoyed how it advanced the metaplot, but many people aren't so appreciative.