There is nothing silly about choosing a pen for its looks. I wonder how many much more important decisions (marriage, real estate, etc.) are made based solely on looks. The pen you chose is certainly a beautiful one and I'm sure you will love it as I love all my Pelikans (notice the plural there

)!
Have you seen the Pelikan Honey? It's also a 400 series and it's a striking pen.
There isn't a huge difference between the 400s and the 600s but once you get to the 800 size, that's where I at least, begin to notice the difference. If you want to see a really cute Pelikan, check out the 320. Now THAT'S a tiny pen but it's just as good a writer as its big brothers!
Of course, I could go on and on about various other brands but then I'd have to be guilty for destroying your budget. (Check out the Yard-o-Led Viceroy Victorian standard. This is one of the most gorgeous pens on the market. It is entirely handmade, solid sterling silver and it writes like a dream. It has enough hallmarks on it to satisfy any skeptic and it is NOT a fortune - depending of course on where you buy it).