I just started using the 1/8" PreciseBits collet for the DeWalt 611 and I can attest that it is VERY nicely machined. I’m using it with a 1/16" Kyocera bit for sign carving in hard maple. The single wrench is nice as well.
For what it’s worth, it appears to be a better deal to buy the standard precision collet kit through Inventables rather than direct from PreciseBits as you can avoid getting the special collet oil included in the kit: https://www.inventables.com/technologies/precision-collet-kit-for-dewalt-611
I can’t imagine you would need the ultra precision collet unless you had a well tuned Shapeoko and were machining metal.
I will definitely purchase the 1/4" collet in the future.
Oh, also be aware that the collet needs to be properly snapped into the nut prior to use…