Note the date on Dave's video's. IET has since stopped selling it, but DER still produces it. IET now sells 6000 version (for high price), which is apparently pretty much the same thing, just ever so slightly more tightly calibrated or something.
Yes, the IET and DER versions of 5000 are basically the same. However, the DER versions may be a few components different/missing (apparently saving cents on some less critical components), and perhaps some other "behind the scenes" differences, like in calibration (or lack of it). But hard to say what could be affected and how, since the facts on the chipset etc. seem to be hidden from the public. Anyway, they do work the same.
I'd recommend buying at least the tweezers and one other adapter (to use as is, or to DIY change it to use whatever cables/clips desired).