Well, there's a mini-review of the Conklin Duragraph
HERE.I haven't tried a Glider yet, but I do own both a Conklin Mark Twain and a Duragraph and they're both very smooth and reliable writers so far. The Duragraph has a 14k gold nib and the Mark Twain has a steel nib. I believe the Glider has a rhodium treated steel nib.
I don't own a Parker 100, but I do have a Waterman Charleston in Ivory/Gold Trim with a medium 18k gold nib. The Ivory/GT is the most attractive finish on the Charlestons, in my opinion. My sample is a bit of a dry writer unlike my Waterman Phileas, but I found that it's a bit finicky when it comes to inks. When I first got it, I used the cartridge supplied with the pen and had no issues, but then I switched to the converter using Montblanc Royal Blue ink and it began skipping all over the place. Only after repeated flushing and switching to Parker Quink did my Waterman start writing as it was meant to.