IRO-bots are organic machines, more or less like humans in day-to-day life. They can feel pain, they need to breathe, eat, drink and sleep. They all have separate personalities and there is no evidence to support that they can be programmed, although they are generally made to fulfill some kind of purpose. They are not created with the capacity to feel or understand emotion but can learn these things, seen when Coheed and Cambria kiss in Year of the Black Rainbow saying that they understand what love is. IRO-bots are capable of producing children when they mate, so it can be assumed that biologically they function more or less exactly like humans. This is backed up by when Ambellina and Claudio found the mutilated body of Sizer and found he had internal organs.
IRO-bots differ mainly from humans in that they cannot really "die" so much as lose their function, hence the phrase "IRO-bot will never die". In order for an IRO-bot to "die" permanently it needs to be disassembled or destroyed to the point where re-building it is completely impossible, such as when Coheed and Cambria are disintegrated by the re-ignition of Star VII.
IRO-bots tend to be stronger, faster, more intelligent, more perceptive, and all around better then their human counterparts. Each IRO-bot has a unique trait or ability, such as Many's ability to multiply and Sizer's transformation. One notable exception to this is Inferno, who is never shown to have any ability beyond the normal enhanced physical and mental abilities. A possible explanation for this is that as he was the first IRO-bot, a prototype, he would therefore would not have the complete functionality of the later models.
The strongest IRO-bots shown thus far are Chase, who is the Vishual and therefore can manipulate reality, and Claudio.