Now I'm second guessing myself. The more I read about both of these the more I worry they may be a little too stiff... (NS is a freestyle board, but sounds like ALL their boards run on the stiff side)
Their boards do run stiff, b/c they are made for any weight range to ride any size. Someone who is 200 could ride a 149cm, according to their reps I've spoken with. Thus, a 155cm deck for you would bar LESS stiff than it would for me (b/c I weight a lot less). So when your looking at NS decks, there really isn't a per se "recomended" length you should be riding. Also, as a new rider, a shorter more menuravble board will help you learn faster. The System is a great board. I would recommend it to anyone.
So, why am I selling it then? I wanted a really short and really soft freestyle board, so I got one (Rome Graft). 90% of the riding I do is at a small-ish local mountain. About 1/2 of that time is spent in the park. We never get powder (eat coast), and they groom the trails A LOT. Hence, for the very limited amount of terrain I get to ride, the Graft suits all of my needs a little better than the System. If I lived closer to a larger mountain, or had enough time/money to go up North (or out West), then there is no question I would want a full quiver of decks to deal with everything. In that case, the System would by my first choice for an all-mountain freestyle deck. But, since I am not afforded that luxury, I can't justify having two boards. There is no question that Graft is a better park board (for me), and no question the System is a better all-mountain board. But since a good chunk of my time is spent in the park, I'm keeping the Graft because it is more park-oritented.
Someone on here once said "Boards are like chicks. You need to ride a bunch to figure out what you like." I've ridden a bunch, and this point in my life, the Graft just suits my park-heavy riding a bit more than the System does.