The reasons the USAAF did not go with it are fairly straight forward.
ETO: They needed a fighter with long range and high alt performance, to escort bombers and combat the LW, which the P-39 had neither. P-38 and P-47 in 1942-3 were the logical types to go with, to partner with the heavy strategic bombers. For that reason neither the P-40 or the P-39 were used by the USAAF in England.
Pacific: They needed again, range, and a fighter with better performance to combat the Japanese types. The P-40 had better handling, and so was kept on as a secondary fighter into 1944, but as the P-38 and P47 became available in the Pacific, and later the P-51 Mustang, the P-39 was relegated to Tactical Recon units in the USAAF. The P-38 was king in the Pacific, it had range (above all), it was fast, it had a heavy warload.
The P39 did see some service in N. Africa, in the ground attack role, untill it could be replaced.
The P-39 just didn't serve what the USAAF needed in a fighter in WW2, unlike the Russians, who wanted a fighter that could fly low and fast, had reasonable low alt handling, range not being that much of an issue (they flew very close to the front), the P-39 was a welcome addition to their own domestic types like the Yak and Lavochkin. It was well built by Russian standards, and despite its quirks, they used anything that could be put to good use against the Germans.