I've heard both good and bad. From what I've gathered quality control is still an issue for Majohn pens. So if you get a good one, they're actually pretty good, but it's a dice roll as to weather you will or not.

My Curidas dries out faster than my Vanishing Point or my Majohn A1. I think the plastic trap door sometimes doesn't close fully, which I think is a design flaw. Too bad, because the EF nib is really great.

Yeah, I don't think anyone would argue that the Vanishing Point is a better pen. I have a Capless (Japan market only Vanishing Point, but with "special alloy" nib.) and just about everything about it is a little better. But the Vanishing Point at least as far as retractable fountain pens go is pretty much the gold standard, so the fact that it's even close says a lot.

I find the plastic design a mixed bag, Overall the construction feels a bit like it won't have the longevity that some of my other pens will, but maybe it'll surprise me. It doesn't feel bad, just not quite as good as say my Lamy Safari. But that kinda' makes sense considering the Safari was meant for school kids, so it was designed to get bashed around a bit. Like if I were to drop my Safari I think the most I'd be worried about is maybe having the ink spatter inside the cap. I'm not sure the Curidas wouldn't actually take damage if I dropped it. But, that's part of the draw of an inexpensive pen, if it does break, it's easier to replace.

I'm not as concerned with the ink drying out, and so far in normal use I haven't had any issues with mine acting oddly. That said I usually take the ink out of my pens and clean them if I'm going to not use them for a while. I don't like to store them inked. I do appreciate the heads up though, and will keep that in mind if I have any troubles of that nature with this pen. It's probably going to get used every couple days though so it won't have a lot of time to dry.
And yeah, the knock is surprisingly long on this, almost double that of the Vanishing Point. But I don't find it makes the pen too unwieldy. One thing that does get me though is that it's thicker than my Vanishing Point, so it won't fit in the pen loop of my notebook. That's not a deal breaker either though, as I'm just as happy to carry it in my shirt pocket and stick a pencil in there for the notebook. It's handy for putting in tentative dates anyway.

It's good to hear Platinum stands behind their pens, that says a lot about them as a company. Nothing makes me less interested in being a repeat buyer than poor customer service.

I noticed this too. Mine's a medium but right from the start it's very smooth. I also kind of like that it's a fatter pen. While it's not great for fitting in my notebook pen holder, it is pretty comfortable (at least to me) to write with. Those two things together make it something I've enjoyed using the last couple days. I've put down about 6 pages with it in that time and my hand didn't get tired of it.
I guess we'll see what the future brings. If it holds up and keeps working well I can overlook it's negatives and overall continue to like the pen quite a bit. And I will admit as someone specifically liking retractable fountain pens I'm definitely a "specific set of needs" case.

As a first experience with Platinum pens I'd say for me it's been a good one.