I am a member of the J Crew Afficionadas Board (jcrewaficionada.blogspot.com) and we generally give low scores to their cashmere and dream sweaters but most people like their merino.
What sweaters are you considering? I have the merino ruffled sweater J Crew currently has and am really pleased by it.
Generally, I am much more happy with the sweaters from Ann Taylor or Banana Republic than my J Crews from a durability and fit standpoint.
love cashmere sweaters, esp. from jcrew. they do pill alot, but come in fabulous colors. a little on the pricey side too. but all cashmere pills. AT offers very few colors and styles. they have nice jcrew cashmeres on sale online right now, bought a few for a good price.