There is now an opaque version of the 3003 and I received five on Monday: Yellow (with a hint of green), light green, light blue (with a hint of turquoise), orange, and purple. I find the demonstrators to be a chaos of colors and surfaces and the opaque ones are soothingly plain. They look rather Germanic to me and remind me of inexpensive, utilitarian German pens. I might have to concede, though, that the plastic seems cheaper.
All of the new pens write as the magenta demonstrator does when it is in a good mood. At last report its moods had been good, very bad, good. Today it was moderately bad -- hesitant to start and much drier than the rest (though remember it has cheap ink in it). They opaque ones all started immediately after sitting for three days and are smooth, wet writers. All six pens have EF nibs.
The cap finial screws into a plastic liner in the cap and the rest of the pen fits into that liner when the pen is capped or closed. This means that the body continuously acts as a wrench to loosen the finial, clip, and liner. This seems like a really dumb design to me. It has previously been implicated in the pens drying out. That is not the explanation with my demonstrator but the blue pen came completely apart while I was writing with it. A well-placed dab of glue might defeat this auto-disassembly feature. (Perhaps they wanted to save us the trouble of having to make a video showing how to take it apart?) While you have the glue out, the trim ring between the barrel and section is also inclined to fall off.
The pen takes what I call "big bore" cartridges, as do many recent Chinese pens. The likely candidates are Parker, Lamy, and Hero 359 cartridges. I have many pens that work with all three, but also pens that work with but 1 or 2 or even possibly 0 of these. The hole diameters of the three are sometimes claimed to be slightly different, and the different shapes can prevent certain of the cartridges from fitting in the barrel. I tried one Parker cartridge and one Lamy-style cartridge from Thornton and have yet to see any fit issue or leakage. Curiously, I am seeing the same kind of seepage of ink between the section and the supplied converter as I have seen between section and Parker cartridges on other recent big bore pens from China.
These pens work great and seem to be tolerant of different cartridges. It's a pity that are not stuck together better.