I got this Harmonie for last Christmas and since then I've used it pretty much all the time for a good long while now. When I got the pen it was fitted with the regular medium nib. Which was a wonderfully smooth and wet write. But not too wet. It was an exceptional nib I have to say. Then, after a month or so of use with no problems whatsoever, I dropped it!
The nib is great, as is the grip. The grib is just molded resin, no frills or anything. Just a grip, but it's so nice to hold and it makes writing rather pleasurable. The pen's barrel and lid are made from metal and then covered in a red and black chequered lacquer. Which is another lovely point about the pen, it's so damned pretty I can stare at it on my desk for a good few minutes before I actually get any work done!
I've currently got it running off of Waterman Florida Blue cartridges, I'm getting a converter soon. The pen writes with this very nicely and the ink dries almost instantly after writing. Smudging is also very, very rare. So, to sum it up, I'd give the Waterman Harmonie an 8 out of 10. And yes, I've used an Edson
*Additional* The converter and ink I purchased from thewritingdesk.co.uk arrived(which was damned quick by the way). The Harmonie works perfectly from it and the Diamine Aqua Blue runs nicely through the pen. So, if you want to use bottled ink, then you can...perfectly! Most of you do, just you know, every little helps