At first, a comparison between a pocket pen and a 'full sized' one might seem a bit unfair. But when it comes to these two, the M300 and M600, it actually makes some sense (at least to me it does!): the price of both is relatively comparable, so with this comparison you should be able to find out which one is best suited for you!
The overall specs of the M300 and M600 are quite the same: resin parts, gold hardware, same color scheme, ... Though there's obviously a noticeable size difference between the two.
|From L to R: Souverän M300, vintage Pelikan 400, Tradition 205, Souverän M600, M805, M1000|
Whereas the M300 is only 11cm capped (for a reference, a kaweco sport is about 10.5cm capped!), the M600 is 13.4cm. When uncapped, the M300 becomes quite unusable. I have medium-sized hands, and it's barely long enough to not dissapear inside my hands! The M600 on the other hand, I prefer to use unposted, the size is just right, and it's extremely well-balanced when unposted.
Another major difference lies in the girth of these two pens. Whereas I would consider the M600 to be a normal sized pen, the M300 is thin. The grip section feels somewhat the same as the Kaweco lilliput. It's not uncomfortable, though I guess most people (me included) prefer a slightly thicker pen.
The nibs on my test models are surprisingly different, but this could be a standalone case. The M300 seemed to be slightly softer, and allowed for some more line variation, it also wrote a slightly wider line, even though they are both Medium nibs! I really enjoyed using the M600 as a workhorse pen, the nib performed spot-on. As I said, the difference between these two nibs could just be a coincidence, though I thought I'd mention it anyway!
In the end, the M300 really suffers a bit from its length. It's definitely not for everyone, people with larger hands will find it to just dissapear in their hands. People with normal or small hands shouldn't really have any problems with its size when posted. Posted or not, it does remain quite slim, so you'll have to figure out for yourself wether or not you like narrow grip sections.
As I said in my review of the M300, it would make for a great pocket pen IF you carry it in a protective case! The resin on these pens isn't the most scratch resistant (Which is inherent to resin though. Pelikan's not to blame here.), so you won't want to just throw this in your purse or jeans pocket! I also think this would pair well with a traveller diary, as its size definitely makes it easy to take with you.
Another drawback you should definitely keep in mind, is that, because it's small, it won't hold as much ink as the other Souveräns do. Especially with a wider nib, you'll find yourself refilling it quite often, which is definitely something to keep in mind!
|M300: posted, in hand|
The M600, on the other hand, should fit pretty much everyone! Its length and girth are perfect. And posted it'll fit even the largest hand comfortably. If there's any pen from the Souverän lineup I'd suggest as a workhorse pen, this would be it. It's not too big, not too small, and it performs great. 'Nuff said.
|M600: posted, in hand|
Pricewise, there's not a whole lot of difference between the two. The M300 is apparently quite a difficult model to make (with all custom parts), which explains why it's almost as expensive as the M600. The M300 comes in at 280 EUR/ 350 USD, whereas the M600 will set you back 350 EUR/ 400 USD.
The smaller size might make the M300 seem like a waste of money, but if you're looking for a great pocket pen, this might be it. In the end, both pens are manufactured to an incredibly high standard, which -in my eyes- makes them both worth the price.