When I first published BeaconReviews.com in the winter of 2003-04, it was obvious there was only one 5-star avalanche transceiver: the original Pieps DSP. 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 mid-2013 resulted in 13 of the 16 avalanche transceivers receiving 5-stars. It became obvious that the scoring system needed to be revised.
Some of these features add a tiny amount to the score (e.g., a multiple burial indicator). Others contribute significantly (e.g., direction/distance indicators). The mathematical model got 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.