I can only speak from my own experiences but at the Airports a good ATSA is worth their weight in gold and truly make a difference to how well and easily you can do your job.
I haven't seen the "us and them" scenario in a long time but then I have viewed it from the ATCO side so I cannot say it does not exist at Airports but the job is different at the airports. Some conversations of how it used to be with some old school guys who saw a huge division between the two grades gave a horrifying insight into how bad that division could be. If the unit is wise then they will put new trainees in with ATSAs for a few weeks before ATCO training it helps them understand just exactly how much they do at the unit.