So I've been trading (mostly) in what up till recently was unclaimed, federation space. Now it's under the care of Edmund Mahon.
So my question is, do I have anything to gain by aligning with Edmund Mahon or am I really better off staying an independent contractor ?
You'll be better off trading in Mahon's space (exploited and controlled systems) if you're pledged to Mahon, because you'll get trade vouchers on your profits starting from rank 2. The value depends on the galactic standing. When Mahon is ranked 1, it's 20% of profits, rank 2 it's 15%, rank 3 it's 10% and otherwise it's 5%. And if you're rank 5 you also make 50% on the profits made from rare goods trading in Mahon's space.
Those are the upsides. The downsides are as follows:
You have to be rank 2 to get the bonus, and the rank is only applied at cycle tick. This means if you're not already rank two now, you'll not get the bonus until next Thursday (the 5th of November), and next Thursday it's unlikely that Mahon will be ranked 1. Rank 2 is much more likely.
Also, when you're pledged to a power (any power), you will be interdicted a lot more often. This is because of the powerplay NPCs now paying attention to you. This is annoying, especially as a trader.