I have used 70+ of the Tayda 2.1 enclosed ones you have linked above in pedals without any trouble and have just received another 30.
The problem I am having from Tayda is in the Cheaper 6.35 Mono Jacks A-4556. On a few ie. 5 out of 100 or so the nut is too big or the thread is too small and cannot be tightened. A real pain. I use plumbers Teflon tape for these but in a way so I still get an earth with the enclosure.
http://www.taydaelectronics.com/hardware/6-35mm-1-4-plugs-jacks/6-35mm-1-4-mono-chassis-socket-jack.htmlTayda are Good. If you don't receive items or are faulty I have received Credits from them in future purchases.
In Australia Purchases are received within a week and no Custom fees like in some European Countries. So the prices are reasonable.