Hey Chris, I used the Tracker2 for many years. It's a great beacon, and it's also pretty simple. That being said, I really think it's worth it to spring for the Pulse. You can leave the factory settings in place for now and then as you grow in your backcountry skiing, you can customize it. I honestly feel like this is the easiest beacon out there to use. There's a reason so many heli ski companies are making this the beacon their clients use. It's stupid easy to use, and that's what you want when it hits the fan. (Be sure to practice too).
As for the mammut to mammut, that's bogus. That being said, the newer beacons are easier to find because of the way they send out their pulse. It's complicated, but the short version is that the new beacons isolate the different signals based on the leading edge of incoming signals. The newer beacons are built for this and thus, a group of new beacons will be easier to find in a multiple beacon search, than a group of old beacons. Hope that helps!