We were under the impression that only ships-of-the-line and other noteworthy vessels that appeared in Star Trek films or televised series were to be included in the standard starships line and that experimental craft would make up their separate exclusives range. Apparently the lines are being blurred somewhat as Eaglemoss continues to dig ever deeper into the Star Trek universe to come up with even more out-of-this-world additions.
That said, their 152nd entrant in the series represents the USS Excelsior Prototype MK1, an Excelsior class starship in service from the late 23rd to (at least the last quarter of) the 24th century. Originally dubbed the “Great Experiment”, Excelsior was the first Starfleet ship fitted with transwarp drive (EMST0152). Though the “experiment” apparently failed, the vessel played a role in the historic Khitomer Accords and became the prototype for Excelsior-class heavy cruisers, serving the front lines of Federation exploration and defense efforts until the end of the 24th century.
Look for the Excelsior to put its neck on the line later this year.