Adam is/was not a good programmer like Satoshi was. Satoshi was in favor of alt coins in Adam is notoriously against them. "Adam put enough effort into proclaiming that Bitcoin was based on the concept of HashCash that, if he was Satoshi, Satoshi would have given HashCash more credit." - Another HN User. Satoshi had a positive attitude and Adam is notoriously unpleasant.
Hal is a great programmer, worked for Phil Zimmerman on PGP. Hal is the first person Satoshi contacted, first person to mine outside Satoshi (op sec). Hal was aware of all the prior works that failed, b-money, bit gold, hashcash, etc. Linguistic analysis of the Bitcoin whitepaper and Satoshi's forum posts most closely match Hal's writings. Hal lived in the same town for 10 years as did Dorian Satoshi Nakamoto. Hal died of ALS shortly after Satoshi disappeared (he knew it was coming and that he couldn't continue).