I have been looking into a few more pens recently, and was looking for something that is somewhere between my Kaweco Student Soul and the Lamy Safari. I like both, but find the Safari sometimes a bit too scritch-scratch and would like to have something slightly larger than the Kaweco, but first of all I wanted to own a piston pen.
The TSWBI Eco series seemed to tick all the boxes, and since I couldn’t decide on a color I opted for the transparent one. Looking at samples I opted for the M-Nib, which is about the same as Kaweco F.
I have learned many things since I purchased the pen. As for example how much the paper-quality effects the width of the line. Depending on paper it is about the same width as the Kaweco, on others the line is much thicker. Very interesting and offers lots of room to experiment with paper and inks.
Generally though I think the M-Nib is too thick for me and an orange one with a F-Nib is already on the way.