Glacern holders and collets are pretty nice quality, especially for the price...
We bought a bunch of Glacern extended reach R8 ER-32 holders that were on sale at $29 a pop and a set of ER32 inch collets recently.
The finish on the parts is great, but the drawbar threads were really tight and not tapped deep enough, so some needed chasing with a 7/16-20 tap before they'd fully seat in the spindle of my work's BPT clone.
The collets are of good quality, too. Their surface finish is excellent and their TIR was less than the spec sheet claimed to boot.
Overall, they're great for the money and the customer service was good. I'd definitely consider buying from them again next time I need more holders. I've also had my eye on a pair of their premium 6" cnc vises, but haven't had the funds to order those yet.