There are a few threads on this topic. I don't have time to find em for you.
I go directly from Cassette to the pC. However, I think going to DAt works for a few different purpposes. Such as, Are you going to have time to do the complete cass>>PC transfer. If not, You may want to pit in on DAt to ensure that you only have to play the cassette once.
Same goes for how sure you are of your transferring technique. If there is a possibility that you may have to do a "re transfer" for any reason, you might want to go CASS>>DAT so that uyou don't have tp play teh cassette more than once.
look for the other threads, they have a lot of good info.
Kyle
edit: I should have said I go directly from cassette >> Echo Gina 24/96 outboard converter box>>Mac G-4 with dual 533 using PEAK BIAS VST.
this reduces any PC added noise. especially since there is no PC involved!!