You won’t do the “team bonding” activities that NATS do. IMHO too much time is spent on these activities in NATS and this is why historically the courses run by the non-NATS colleges are so much shorter. That said, NATS may still do these with you at a later stage. Other than that, the actual courses run by NATS and Global are the same, the end result is also the same e.g. you get the same Student ATCO Licence whether you went to Global or NATS.