I use a broken DR680 (two dead channels) for all my DAT and R2R transfers, and it is good enough for me. The DAT source, even on studio quality DATs, is only 12 or 16 bits, and when I do an A-B comparison between the original DAT and the digital transfer, my ears can hear no difference. R2Rs do have an ambient quality that makes any digital transcription difficult. Well, not difficult, I should say hard to capture that ambient quality.
I have done over 2,000 DAT transfers in the last two years for a radio station, all 16-24 track masters of name groups, and the DR680 works for me. Sony 7030 > Hosa AES Interface> DR680 > SD Card. Then download the SD Card to the computer.
Let your ears be your guide ............