If you mean Finn and Jannah's squad, the First Order troops aren't conscripted but stolen from their families at a young age (Partly a warped version of the Jedi's ways), and it's implied that the force had a hand in influencing their change of heart.
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From the Empire, new canon-wise there's Barcona but a lot of the other Imperial defectors seem to be mainly fleet officers and especially pilots (Rodhi, Inferno Squad, Yrica, Wedge, Sabine, Thane etc.) Might have something to do with TIEs in general being more expendable/cheaply made (Although Thrawn tried to develop better ones the Empire wanted to finish the Death Star instead).