Which just leaves the factions. There are three private military companies in total to choose from. The futuristic Raven, warrior-breed Valor and terrorist-chic SVER. The guns differ but it's mainly cosmetic.
It didn't feel like any one machine gun or sniper rifle stood out hugely at the lower character levels, although it's possible differences will appear once you've levelled up more. Essentially you're picking a label that identifies you. So, to finish, here's a quick guide to each PMC:
Based in Austria this is a rich, tech heavy bunch. They're all about cash, shiny body armour, fancy guns and VR training. They have seen the future and shot it. Pick this lot and you're basically saying you believe Halo to be a true and accurate representation of current military practice.
Pronounced 'sever' it stands for Seryi Volk Executive Response. Based in Eastern Europe everyone has posh English or Russian accents making them sound like the bad guys from a Die Hard movie, only with ashoestring budget - they dress like Viggo Mortensen in The Road and most of their gear is rusty, 70s and 80s Chinese and Russian knock offs.
The boy scouts. Full of notions of honour and nobility on the battlefield they're pretty much an army of Solid Snakes. They're also the most like a real military force with current weapons heavily biased towards American equipment. No one's actually said 'Hoo-wa!' over the headset yet but it's in the post.