Hey Hank-
Just my two cents- I am sure a good 5C collet chuck, when set up properly, is perfectly accurate. Alternately, they increase the extension of the workpiece from the end of the spindle. And remember you will be turning that handle quite a bit sometimes if speed is an issue for you.
Answering your question though, I would think that a collet mounted INSIDE the spindle via lever-closer or drawtube would be inherently more accurate just because there is less chance for runout unless there is debris or a burr somewhere, and minimizing the "hangout" from the end of the spindle.
I think your question may come down to more convenience or speed, unless you know you will be taking crazy-heavy cuts, then I would go lever-closer/drawtube.
As regards speed you can't beat a lever-closer.
Ray C, a moderator here, loves the Collet chuck over a closer. I can't remember the key reason (sorry Ray!), but you can ask him or search it here.
Also, the lever-closers take up a lot of space behind the headstock and make noise.
I hope I don't cause trouble to introduce MY favorite, which is the drawtube! Hah hah! Compact, quiet, and enclosed in the spindle. Usually not as expensive as a chuck or a lever-closer either!
What machine are you running?
Bernie
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