Correct -- the Tracker pioneered the entire category of the dual-antenna directional beacon.
Since then, other companies (Pieps, Barryvox, Ortovox, ARVA) have introduced a third antenna, which eliminates nonsensical readings (spikes, nulls) during the pinpointing phase. The Tracker 2 (January availability?) will add a third antenna.
Another development has been various features for aid in multiple-burial searches. The Tracker will add an indicator light for that, but will not introduce any sort of masking feature (like with Pieps, Barryvox, Ortovox, ARVA) so as to remain true to its goal of being very easy to use, with no additional features whose added complexity can cause potentially cause confusion.
You can drive yourself crazy overanalyzing all the choices and trade-offs:http://www.wildsnow.com/1476/avalanc...-review-intro/
. . . but if you're not enamored of gizmos, and want to save yourself some $$, a Tracker on sale is a great choice.
Also, once that Bentgate sale ends on Nov 18, then starting Nov 21 through Dec 1, the Tracker will be $230 at REI.