Another thing, coming from a Cork Irish perspective is listening to his pronunciation of Déaglán, where he has /i@/ in the first syllable - where Amhlaoibh Ó Loingsigh would have had /ia/, with a very open /a/ in the second element of that.
Listening to the Doegen recordings of a Kerry native -
https://doegen.ie/LA_1090d3 - it should be /ia/ in Kerry too. Aidan transcribes all these words with /ia/ in the textbook, and not /i@/, so he must know his pronunciation is wrong.
The book is good, although it needs supplementing with more dialectal information. Peig's nín for níl doesn't get a look in.
Tá siad for táid siad is also painful to hear in his recordings.
He makes a good attempt to pronounce both broad and slender R properly each time - he has to get a "tick" for that. He does not use the English R, as 100% of Irish learners do.
I'm not sure about the broad N in anois, which he favours - my sources tell me it is slender. ainIS.
Another thing that might be a dialectal difference is that he has compórdach, with /k@m/, but what I've learnt of Muskerry Irish is cúmpórdach with /ku:m/.
He gives the verbal noun of cuirim as cur, but states it is /kir/, with a broad R. It can be a slender R. He has siúcra and not siúicre and claims ubh is feminine and pronounces it /uv/ and not /ov/.