Before you head out to the three alien playfields, you might want to read up on what the drops do, which upgrade guns, which can turn your boots/glasses into Inf/Pen rings, which make the new helms, etc. You can check the loot which the bosses of each sector drops.
During a raid, be it in a city or in an alien playfield, loot has always been a reward that people have wanted, be it for personal use or for profit.
So how does loot get distributed fairly?
The answer is a bit complex. In a city raid, things are simpler. The organization hosting a raid in their town usually have control by having teams set loot to team leaders who are members of their org. Boss Loot which is used to make armor or weapon upgrades are saved for distribution after the raids, weapons are given to those able to use them at the time or in the near future. Loot from regular alien mobs are usually FFA (free for all).
Nodrop items are a tougher thing to give out, since there is a limited time to grab them before they vanish. Some nodrop items are profession specific, which makes things easier when choosing who should get them. The basic rule in a city raid is: if you can use it now or soon, you probably will get it. Raffles for items is not common, since the most valuable are located in the alien playfields.
Alien Playfields raids are usually run with a raiding bot, which allows raid leaders (or administrators of the bot) to raffle or auction rare items during and at the end of the raid in a fair way. There are times, when a raid may not be run using a bot, which means that it will probably be FFA (free for all) so always be aware how the raid is being run from the start.
Note: If nobody in the raid can use a nodrop item which is profession specific, check with friends, one may need the item and it is possible to make it to a city in time before the corpse vanishes with a yalm and using the right whom-pas or grid.