In the 90s, I owned a Parker Sonnet FP with a broad gold nib and I always regretted selling it. A few months ago, I got another NOS Sonnet from ebay. A deep blue laque model that was discontinued. The latest Sonnets have a metal band on the cap that I do not like at all.
What I like most on this pen is, of course, the wonderful marble blue finish. However, the winter sun has made the gold platings in these pics appear to be stainless. They are not.
I had the medium nib exchanged for a broad as I use this pen mostly for greeting cards or signatures. If you can live with the somewhat slim barrel of a Sonnet, you should try one out. They are very reliable pens.
I find Parker cartridges somewhat expensive, but the piston converters supplied with the Sonnets work very well. You should stay away from the inexpensive sliding converters. I had to trash several of them as they stopped working. I´d rather fill up cartridges with syringes from an ink bottle before buying those crappy things again.