There is no one standard. Really within a faction, you'll generally just be using that faction's weapons. Rxceptions might be, for example, the Bounty Hunter plot - where weapon use is more determined by what you afford on the market rather than what nationality you are.
You'll find that Mach-speed level missiles of various types (high explosive, anti-matter, etc.) are more or less in the armory of every faction you might be playing as. The same goes with laser based weaponry and particle accelerators. On a personal level, power armor is so common that fighting without it is more of a rarity and death wish, and while many weapons available on that scale or laser/plasma/energy-based a majority are generally slug-throwers of some kind or another.
The general rule of thumb is that sleek and aesthetically pleasing is going to be Yamatai's approach, while Nepleslia adopts a more "pulled from an action movie" looks and thrills-before-thrills. Both will get the job done and its mainly a matter of personal taste if you aren't wanting to dig around and constantly be comparing wiki stats.
Other factions tend to drfit to one side or the other of the two stated approaches while at the same time the creators have added their own flare to keep things different and fun.
In short: every faction has their own ordnance and outside of a few third party suppliers, they generally keep to their own kit, most all arsenals on a faction-wide scale are comparable, and soldiers properly equipped can quite literally fly through space at Mach 1>.