Myself, I don't much care for the Delco conversion. And I'm running one currently quite successfully.
The units are big, and don't look right imo. Visually I much prefer the little Bosch or Nippondenso alternators. Their appearance is much more suited to the application.
Functionally a good Delco is a fine alternator. BUT...finding a good Delco in the sea of cheapo poorly rebuilt units is a bit expensive. Yes, you can buy a rebuilt Delco for under $30, but boy do you get what you pay for!
I'd have no fear of running a one-wire alternator on a street car. They don't work well on tractor conversions. But that's because they take a fair amount of rpms to kick in and start charging. Not a problem on a car engine, but somewhat of a problem on low reving tractor engines. On a Triumph with all the wiring in place for a 3-wire alternator, I wouldn't bother with the slight expense of a 1-wire alternator.