Most changes have been positive so far. Such as having to opt in and being in the program automatically, instead of doing a crappy interview where they'd give you the boot for whatever reason. I did the aviate interview, and in the first 5 min of the interview, the United Captain straight out accused me of lying about my pilot certificates. It was a very negative experience and left a bad taste in my mouth. The opt in is a huge plus.

As I stated above, if it's a big change, they will make it so that people who were following the old rules, could still follow the old rules.