I just read it is an improved bartlett with 1/3 larger fruit. Said nothing about keeping qualities.

Here's an abstract from a technical paper:
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STORAGE CHARACTERISTICS OF SPARTLETT PEAR
Author: M. Meheriuk
Abstract:
Size in Spartlett pear was considerably larger than in Bartlett pear (380 g vs 180 g). Late harvested Spartlett pears were lighter in skin color, had less titratable acidity and were lower in firmness than earlier harvested fruit at harvest and during storage. Senescent scald was always present in Spartlett pears stored in air for 180 days but could appear as early as 120 days of air storage. Quality parameters in 2% O2 + 2% CO2 or 3% O2 + 5% CO2 were comparable but superior to those in air storage. Controlled-atmosphere storage prevented senescent scald and reduced the incidence and severity of core breakdown. The cultivar has a shelf-life of 7-10 days and can be stored under controlled atmosphere in excess of 180 days
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Another site said hardy but susceptible to fireblight.

Should be able to locate more info with a brief search

Here is a link that might be useful: abstract

Where can the tree be purchased? I live in the New York City area.