they tend to be contracted to work for government officials such as POLAD and generally are a good bunch. they have the added factor that they will get government support if required. ie soldiers coming to help out. this was the case in herrick 4, it may have changed but i dont think so. they also get well looked aftert while they are away with lots of creature comforts.
A lot of guys I know work for this firm. They are very well respected both in the services they provide and in the training they offer. If you are able to secure a position with a firm like Armor then you shouldn't have any worries about the unit/colleagues you'll be operating with.