I use Biotech and I do like the toe nail clip better than to pull the breast feathers. The toe nail clip is really quick and the birds don't seem to mind much, of course I only clip a tiny piece at a time to make sure I only cut enough to get a couple of drops of blood, as you don't want to cut too much of the quick.
Make sure to clean the toe nail and clippers with alcohol first and I usually do not use the first drop of blood, I wipe that one away then if you massage gently the toe, the blood gently drains a bit.
You can't use molted feathers, they do have to be pulled. I myself do not like to pull feathers. But it's just me. Besides, with the blood, I also send in a cloaca sample and test for diseases as well such as PBFD for example.