My wife and I have been using the Pieps DSP beacons this year. We previously used Ortovox F1 analog beacons, so I can't compare them to the Trackers.
The Pieps DSP is very easy to use. My wife & I raced several times in our backyard with one of us using the Pieps and the other the Ortovox. The Pieps user was consistently faster because they could pretty much run in the direction that the beacon pointed. The Ortovox user had to stop to re-aim from time to time. We are both pretty skilled with the analog Ortovoxes, so it wasn't a case of operator error.
My seven & nine year old daughters were both able to quickly find a buried beacon using the Pieps after only a few seconds of instruction.
The multi-burial detection functions do not work with 100% consistency. The beacon has a scan function, in which it can assess an area and tell you how many beacons are buried within a 5 meter range, a 20 meter range, and a 50 meter range. That function seems to work quite well. In search mode, however, it sometimes reports multiple beacons even if there is only one transmitting. This mostly happened when we were searching for our old Ortovox analog beacons. You are also supposed to be able to suppress the signal from each beacon that you find in a multiple burial. We weren't able to consistently suppress the signals from our older analog beacons.
I don't particularly like the Pieps harness, although I'm getting used to it. I found the old Ortovox harness more comfortable. The Ortovox was also designed so that it was turned on by putting on the harness, so it was almost impossible to put the beacon on without also turning it on. I miss that feature. My wife & I have both skied all day and then realized that our beacons were not sending. Hopefully that's a mistake that we'll each only make once. We're much more careful about turning them on, now, and about checking each other.
We did not get the advanced versions with temp/compass/altimeter. The user manual states that the unit does not send while it is performing any of those functions. It does automatically revert to sending after two minutes.
All-in-all I'm quite happy with these beacons and have ordered two more for my kids.