Until it wears out and no longer 'clicks' in place.
I got myself 2 of these PenBBS 355's.
I think they're great value, though I'd personality be cautious with longevity.
The first point of concern is how the piston becomes stuck in place without moving it for an extended period. The first 355 I got was the Galaxy Blue version. It's not transparent/translucent and I was lost with what was happening with the filling system. In my opinion, this filling system should be produced only in pens with transparent or translucent barrels that allow for you to see/confirm the rod screwing in and out of the piston. Youtube videos were a 'godsend' in providing info on how to use the filling system and to assure me of just how much I could push on the piston to free it from it's stuck position. After freeing it, it moved very nicely indeed. I filled the pen and used it for a while. I decided to try another ink in it and the piston was stuck again as when I just got the pen. Again, a firm push freed it and I was back in business.
I just got the transparent version and the experience with the filling system was identical in terms of how stuck the piston initially was. A firm and confident push on the rod freed it.
Both nibs have required a little tuning on 12000 micromesh paper to get out some scratchiness, despite pretty much well-aligned tines. After this, they've been great. The nibs are like nails with very little flex/springiness to them. However, I'm finding myself a fan of the up-turned tip of the nib. The fine nib on my 1990's Montblanc149 is very similar in performance and tip format!
So, out of the box, these pens work, but I am not expecting too much from them long term, unless one is willing to change parts. I suspect that they will do best if used continuously; rather than intermittently, with extended periods storage. The piston may well become stuck. You'd have to be sure to disassemble, clean and smear silicone on the piston prior to storage. If you're into that sort of ritual, then I don't see why it should be fine.
Overall, one shouldn't complain too much about these pens. They're incredible value and I find them more useable than a few very expensive pens that I've tried before.
IMO, the 308's are more reliable since they are less complicated. The nibs I've used on the 308's have been bang on (I've tried 2 so far). If you want a lot of ink in one, then eye-dropper it.
Edited by maclink, 12 January 2019 - 11:30.