Eusebius talked about the Didache in a negative way:
Since we are dealing with this subject it is proper to sum up the writings of the New Testament which have been already mentioned. First then must be put the holy quaternion of the Gospels; following them the Acts of the Apostles. After this must be reckoned the epistles of Paul; next in order the extant former epistle of John, and likewise the epistle of Peter, must be maintained. After them is to be placed, if it really seem proper, the Apocalypse of John, concerning which we shall give the different opinions at the proper time. These then belong among the accepted writings.
Among the disputed writings, which are nevertheless recognized by many, are extant the so-called epistle of James and that of Jude, also the second epistle of Peter, and those that are called the whether they belong to the evangelist or to another person of the same name.
Among the rejected writings must be reckoned also the Acts of Paul, and the so-called Shepherd, and the Apocalypse of Peter, and in addition to these the extant epistle of Barnabas, and the so-called Teachings of the Apostles; and besides, as I said, the Apocalypse of John, if it seem proper, which some, as I said, reject, but which others class with the accepted books. And among these some have placed also the Gospel according to the Hebrews, with which those of the Hebrews that have accepted Christ are especially delighted. And all these may be reckoned among the disputed books.