When i saw the TC1000, i started regretting buying a lowly Epia800 (though i bought it second hand so i cant really complain). Onboard PSU makes for more space savings, and certainly costs less than getting a separate Opus.
But i can think of 3 reasons why people would stick to the holy Opus:
1) It can handle down to 7v or something like that
2) It has shutdown/startup controllers.
3) Onboard PSU for TC1000 is only 60W - means you are restricted to Laptop drives and minimal USB devices. Opus handles more
However i'd take the TC1000 - Think of how easy it would be to fit that into a single din headunit!!!
I think that the Carnetix CNPX2160 (or whatever it is - there is only one!!!), would be perfect for that. Its a 12V revulator which handles down to 7V as well, and has shutdown controllers as well!
I know that if i started again, i would choose the TC1000...