My son graduated the academy in 2012. He wanted to go to grad school, but was also torn between being a pilot and being in Special Ops. He took the pilot slot. Got selected to grad school. He's currently in his last few months of grad school. At the end of his 2nd year of grad school, he decided that he really wanted to try out for Special Ops. He got permission to try out. He applied and made it through the first part of selection and was invited to go to Florida for the 2nd phase. Only about 25-27 was selected to go to the next phase. This phase is very physical and leadership. Not sure how to explain it, but suffice it to say that out of the 25-27 that started, only 12 made it through. The others either dropped out or were let out. Now, the 3rd phase. Final selection. Out of the 12 that made it through "Hell Week". Only about 5 were selected. My son was NOT one of those 5. However, during his debrief, the Colonel said he'd really like him to try again in the spring. So, into his 3rd year of grad school. my son went back to Florida this past March. Again, only about 25-27 were invited. Only about 12 made it through. My son made it through again. Final selection, they chose about 5-6 out of the 12. This time he did make it. He's finishing grad school at the end of the summer; turned down the pilot slot; and will be an STO (Special Tactics Officer) starting school in Florida in September.
First, I'm not sure if this process I mentioned above is just for STO's, or if it's the same for CRO's and ALO's also.
From his description, and that of a couple of other STO's that I know, here are some differences between STO, CRO, and ALO. STO is assigned permanently to Air Force Special Operations Command. (AFSOC). Their job is specifically "Special Operations". It's Special Operation Air Control with training in Combat Contra, Air Traffic Control, Jumping, Diving, and many others. ALO is "Conventional" Air Control in military environments. Is it possible for an ALO to be assigned to a "Special Operations" mission? I assume it's possible, but I don't know for sure. But again, they are mostly conventional. The CRO (Combat Rescue Office) while in charge of the Para-rescue, aren't themselves actually trained at being an EMT like the PJ's. The STO are involved however with some Combat Search and Rescue. So in a way, the STO does pretty much what a CRO and ALO does, but not the other way around. And the STO is full time Special Operations, while the other two can be in a number of commands. Matter of fact, it's not uncommon for some pilots to do a tour as an ALO and then go back to flying. Whereas the STO is only Special Ops.
Also, for what it's worth, there are only about 130 STO's in the Air Force. I'm not sure how many CRO's and STO's there are.
Not sure if this was much help, but it explains a bit of difference. Mainly "MISSION" differences. And the STO is Special Ops and trains to do a lot more and be involved with a lot more other military branches Special Ops more directly. Good luck. Mike.