On the feed / see message from Fountainbel (Francis) in this thread, dated 10 April. That sets out the design parameters they have set for the feed. It seems that Conid has (or had) issues with their feeds performing up to their own design standard under all pressure conditions. This is why they offered the choise to wait until the feed is perfected or getting the current version of the feed.
I chose the current version of the feed. Seems to work OK but of course I have not done any rigorous testing under all pressure conditions.
I only have one demonstrator previously (Pelikan M205). This is my first large demonstrator. The CAISO performs well. Opening and closing the cap has a slightly more resistant feel to it than caps usually, or let's say compared with FPN Blue Pearl (which is also a king-size Conid). I assue that this is because of the CAISO system engaging. The cap seals very securely.
I have not been super careful with the pen... Don't panic. The CAISO goes into one or two pen leather pouch, and that pouch has gone into a cloth "mini bag" at times with keys and such. This mini bag has then been tossed around, thrown into my gym bag or swimming bag, is then taken out of the swimming bag and pushed into a secure safe locker at the pool after a bike ride - repeat this a couple of times - and I see specks of ink on the inside of the cap. These are like the result of the rough handling and bumps and whatnot when riding the bike, and the specks are small enough that they must have flown loose from the feed.
I have the rhodium plated gold nib, bold ground to cursive italic. A very nice grind. The nib is very expressive.
The Conid filling mechanism is easy to use and it is nice to see what is going on. Though I must admit, when I tried to do the first fill with water it did not fill up I engaged the seal, pushed down (expelling air into water), and pulled up. No water in the barrel. Flabbergasted, I let go of the knob - and the seal/rod/piston was pulled down automatically! Retry, same result. I realised that I pushed all air out and when pulling up I created a "vacuum" (or rather, very low pressure barrel) which then sucked the piston back down again. I screwed the cap back on, that must have released the CAISO system somehow, and after that I had no trouble with either water or ink.
The engineering and manufacture quality of the pen is superb.
I like the look and feel of the titanium parts.
Conid can be slow to respond to emails, and to get the orders delivered, and this whole CAISO process has been a long slog. But when you hold one of their pens you recognize that they do not compromise on quality.