The obligatory: DV is never an optimal compression for NTSC, due to 4:1:1 color loss. However, for Mac, it's really the only decent solution. Given all the worse Mac choices, DV isn't so bad. This is why video was always a Windows world, for everything from capture to authoring.
But you know all this, mostly rhetorical for future thread readers.
Now, with that out of the way...
The DAC-100 is a nice box, essentially the same as the Canopus ADVC-100, but a few $$ less (both when new, and usually used). It often gave less problems than the Canopus, too. It hardware encodes to DV 4:1:1 internally, and passes that encode to the computer over Firewire.
You're having a thought exercise that applies to all video...
You can usually expand 4:1:1 to 4:2:2 or even 4:4:4/4:4:4:4 (FYI: overkill) with no quality loss. It's no different than encoding a lossy codec like MPEG or H.264 back to a lossless codec. I'd not exceed the "lossy" (but not really) ProRes422. ProRes 4444 is just ridiculous here.
The only advantage of DV as DV is 13gb/hour, instead of the huge files from ProRes. Then again, ProRes is semi-lossy, so not as large as lossless (30-40gb/hour), at about 20-25gb/hour for ProRes422. If there are for permanent archives, sure, smaller is better (without compromising quality). But if temporary working files, I wouldn't cry over 5-10gb/hour.
Your Mac setup is much newer than mine, so can't advise to closely on it. Things have changed quite a bit (on Mac) in the past 5+ years. It doesn't have the legacy compatibility like Windows does software-wise (noting that Windows XP>10 legacy hardware/video is not great). So some options and placements are vastly different now.