When I first published BeaconReviews.com in 2003, only the original Pieps DSP deserved five stars. At that time the Tracker DTS (and similar two-antenna transceivers) were easy to identify as 4-star transceivers (solid performers, but with shorter reception ranges and without a third antenna to resolve spikes). Using that same scoring methodology in 2013 resulted in 13 of the 16 avalanche transceivers receiving 5 stars. It became obvious that the scoring system needed to be revised.
In an effort to minimize subjectivity, I created a mathematical model in the Fall of 2013 that calculates the scores based on information in the comparison table. I revised the model again in late-2019 to adjust for the cluster of transceivers that received 5 stars.
The current scoring model uses the following factors to determine the number of stars.
Some of these criterion influence the score significantly and others have minimal impact. The mathematical model gets us close to a final score, but there are still important considerations that aren't contained in the "comparison table" (e.g., ease of use, accuracy of the directional indicator, consistent marking of multiple burials, absence of a continuous carrier, etc). Jonathan and I made a few minor adjustments to the calculated scores to compensate for these factors.
Suffice it to say that any transceiver with a score of 4.0 is a solid contender and would have received 5 stars under the old system. The individual reviews and the comparison table will help you to further parse out the features that are important to you.