Of the ones you mention I only have/had the Platinum 3776 and the Pilot CH92, both with regular M nibs. The line width of the pilot was a wee bit thicker than the platinum. It really depends on what you like. For me it was the Platinum (and usually I don't like cigar shaped pens).
My impressions are:
The platinum 3776 nibs have a little bit of feedback, which I like because it gives me more control. The ink capacity is ok and not a problem for me. They are smaller pens (I believe the 74's are of the same size) but post very well. They are also lightweight, but posted have a good weight for me. Finally, they are gorgeous - my son and I have the Chartres Blue and my wife the Bourgogne Red, all Medium nibs.
The Pilot CH92 had a very smooth nib, too smooth for my liking. It is well constructed and a little larger and heavier than the Platinum. The piston works fantastically and, in fact, it is the only pilot with a decent filling system IMO (I dislike all of pilot's converters: the con-20 and con-50 are ridiculous, and the con-70, despite having a great capacity, is my definition of pain both to fill and clean. Of course, this is just my opinion). What I disliked the most on the CH92 was the appearance, it seems to me that pilot put together parts of different colors without any regard of how they would go together. Of all the pens that I ever bought, it is the only one I let go. That said, I didn't need another piston filled pen nor another demonstrator, and of the three pilots you mention I would still get the CH92.
I must say that I have a strange relationship with pilot: all their pens have something that annoy me, be it the filling system, the aesthetics, etc.. Yet I keep buying them, because they are very good pens - they are just unable to make me really love them. The only exception is the Vanishing point, that one I love (despite the ridiculous capacity of the converter
). And, true to form, currently the Vermillion Custom 845 is a strong contender for the next pen I'm going to buy. Go figure
Good luck in your decision, I believe any of them will be good pens and something tells me that whatever you decide now, you will probably get one of the others down the line.
Edited by Lam1, 03 December 2015 - 09:04.