I think one of the biggest and most annoying differences for me is that odt guys don't use the interphone. That gets annoying fast considering I still use my trusty DCs. I've also known pdt crews to turn the batteries off even when they see us coming out to the airplane. I've known a few people to have to abort starts because of stuff like that. There aren't many huge differences between pdt and alg, but there is a lot of small stuff like that.
As far as shock is concerned, I still see a lot of anti-ALG sentiment outside of MDT. I've heard everything from sighs to an "oh youre one of them" when true pdt crews find out I'm from MDT. I think it would definitely be a shock for an F/O transferring from the anti-alg sentiment found down south to the anti-pdt feelings I know many MDT crews have. Just a big culture difference.