They are slightly different, and this caused a bug in tenXer because we were expecting the string version of newValue. (I'm fixing that expectation in tenXer, but still better to be consistent because others might have the same issue.)
Example excerpts from https://tools.tenxer-corp.com/conduit/method/maniphest.gettasktransactions/
auto resolve
{ "taskID" : "5493", "transactionType" : "status", "oldValue" : "0", "newValue" : 1, "comments" : null, "authorPHID" : "PHID-USER-2d7perc36s5g6pd4dq7i", "dateCreated" : "1365780938" },
manual resolve
{ "taskID" : "5493", "transactionType" : "status", "oldValue" : "0", "newValue" : "1", "comments" : "", "authorPHID" : "PHID-USER-2d7perc36s5g6pd4dq7i", "dateCreated" : "1365783330" }