We looked but bought a house that a builder was in teh process of building instead.
A few things to consider - take a good look at exterior wall construction - in a modular you'll want 2 x 6 exterior studs if at all possible. Not just for stability but for insulation (plus you get nice window sills) Also - make sure the pitch of the roof is steep enough and ask about making sure you have no trusses - or as few as possible if attic space is important to you.